diff --git a/declarations/keywords/undefinedAsNull.d.ts b/declarations/keywords/undefinedAsNull.d.ts
new file mode 100644
index 0000000..3509652
--- /dev/null
+++ b/declarations/keywords/undefinedAsNull.d.ts
@@ -0,0 +1,8 @@
+export default addUndefinedAsNullKeyword;
+export type Ajv = import("ajv").Ajv;
+/**
+ *
+ * @param {Ajv} ajv
+ * @returns {Ajv}
+ */
+declare function addUndefinedAsNullKeyword(ajv: Ajv): Ajv;
diff --git a/declarations/validate.d.ts b/declarations/validate.d.ts
index a04b6dd..8abd69a 100644
--- a/declarations/validate.d.ts
+++ b/declarations/validate.d.ts
@@ -8,6 +8,7 @@ export type Extend = {
   formatExclusiveMinimum?: boolean | undefined;
   formatExclusiveMaximum?: boolean | undefined;
   link?: string | undefined;
+  undefinedAsNull?: boolean | undefined;
 };
 export type Schema = (JSONSchema4 | JSONSchema6 | JSONSchema7) & Extend;
 export type SchemaUtilErrorObject = ErrorObject & {
@@ -22,6 +23,33 @@ export type ValidationErrorConfiguration = {
   baseDataPath?: string | undefined;
   postFormatter?: PostFormatter | undefined;
 };
+/** @typedef {import("json-schema").JSONSchema4} JSONSchema4 */
+/** @typedef {import("json-schema").JSONSchema6} JSONSchema6 */
+/** @typedef {import("json-schema").JSONSchema7} JSONSchema7 */
+/** @typedef {import("ajv").ErrorObject} ErrorObject */
+/**
+ * @typedef {Object} Extend
+ * @property {number=} formatMinimum
+ * @property {number=} formatMaximum
+ * @property {boolean=} formatExclusiveMinimum
+ * @property {boolean=} formatExclusiveMaximum
+ * @property {string=} link
+ * @property {boolean=} undefinedAsNull
+ */
+/** @typedef {(JSONSchema4 | JSONSchema6 | JSONSchema7) & Extend} Schema */
+/** @typedef {ErrorObject & { children?: Array<ErrorObject>}} SchemaUtilErrorObject */
+/**
+ * @callback PostFormatter
+ * @param {string} formattedError
+ * @param {SchemaUtilErrorObject} error
+ * @returns {string}
+ */
+/**
+ * @typedef {Object} ValidationErrorConfiguration
+ * @property {string=} name
+ * @property {string=} baseDataPath
+ * @property {PostFormatter=} postFormatter
+ */
 /**
  * @param {Schema} schema
  * @param {Array<object> | object} options
diff --git a/package-lock.json b/package-lock.json
index bcfc0cb..e790f60 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -5,6 +5,7 @@
   "requires": true,
   "packages": {
     "": {
+      "name": "schema-utils",
       "version": "3.1.2",
       "license": "MIT",
       "dependencies": {
diff --git a/src/ValidationError.js b/src/ValidationError.js
index f70fda0..a01f017 100644
--- a/src/ValidationError.js
+++ b/src/ValidationError.js
@@ -535,9 +535,17 @@ class ValidationError extends Error {
     }
 
     if (schema.enum) {
-      return /** @type {Array<any>} */ (schema.enum)
-        .map((item) => JSON.stringify(item))
+      const enumValues = /** @type {Array<any>} */ (schema.enum)
+        .map((item) => {
+          if (item === null && schema.undefinedAsNull) {
+            return `${JSON.stringify(item)} | undefined`;
+          }
+
+          return JSON.stringify(item);
+        })
         .join(" | ");
+
+      return `${enumValues}`;
     }
 
     if (typeof schema.const !== "undefined") {
diff --git a/src/keywords/undefinedAsNull.js b/src/keywords/undefinedAsNull.js
new file mode 100644
index 0000000..6fab2b5
--- /dev/null
+++ b/src/keywords/undefinedAsNull.js
@@ -0,0 +1,96 @@
+/** @typedef {import("ajv").Ajv} Ajv */
+
+/**
+ *
+ * @param {Ajv} ajv
+ * @param {string} keyword
+ * @param {any} definition
+ */
+function addKeyword(ajv, keyword, definition) {
+  let customRuleCode;
+
+  try {
+    // @ts-ignore
+    // eslint-disable-next-line global-require
+    customRuleCode = require("ajv/lib/dotjs/custom");
+
+    // @ts-ignore
+    const { RULES } = ajv;
+
+    let ruleGroup;
+
+    for (let i = 0; i < RULES.length; i++) {
+      const rg = RULES[i];
+
+      if (typeof rg.type === "undefined") {
+        ruleGroup = rg;
+        break;
+      }
+    }
+
+    const rule = {
+      keyword,
+      definition,
+      custom: true,
+      code: customRuleCode,
+      implements: definition.implements,
+    };
+    ruleGroup.rules.unshift(rule);
+    RULES.custom[keyword] = rule;
+
+    RULES.keywords[keyword] = true;
+    RULES.all[keyword] = true;
+  } catch (e) {
+    // Nothing, fallback
+  }
+}
+
+/**
+ *
+ * @param {Ajv} ajv
+ * @returns {Ajv}
+ */
+function addUndefinedAsNullKeyword(ajv) {
+  // There is workaround for old versions of ajv, where `before` is not implemented
+  addKeyword(ajv, "undefinedAsNull", {
+    modifying: true,
+    /**
+     * @param {boolean} kwVal
+     * @param {unknown} data
+     * @param {any} parentSchema
+     * @param {string} dataPath
+     * @param {unknown} parentData
+     * @param {number | string} parentDataProperty
+     * @return {boolean}
+     */
+    validate(
+      kwVal,
+      data,
+      parentSchema,
+      dataPath,
+      parentData,
+      parentDataProperty
+    ) {
+      if (
+        kwVal &&
+        parentSchema &&
+        typeof parentSchema.enum !== "undefined" &&
+        parentData &&
+        typeof parentDataProperty === "number"
+      ) {
+        const idx = /** @type {number} */ (parentDataProperty);
+        const parentDataRef = /** @type {any[]} */ (parentData);
+
+        if (typeof parentDataRef[idx] === "undefined") {
+          parentDataRef[idx] = null;
+        }
+      }
+
+      return true;
+    },
+  });
+
+  return ajv;
+}
+
+export default addUndefinedAsNullKeyword;
diff --git a/src/validate.js b/src/validate.js
index e364cd2..8173b61 100644
--- a/src/validate.js
+++ b/src/validate.js
@@ -1,4 +1,5 @@
 import addAbsolutePathKeyword from "./keywords/absolutePath";
+import addUndefinedAsNullKeyword from "./keywords/undefinedAsNull";
 
 import ValidationError from "./ValidationError";
 
@@ -27,10 +28,11 @@ const memoize = (fn) => {
   };
 };
 
-
 const getAjv = memoize(() => {
   // Use CommonJS require for ajv libs so TypeScript consumers aren't locked into esModuleInterop (see #110).
+  // eslint-disable-next-line global-require
   const Ajv = require("ajv");
+  // eslint-disable-next-line global-require
   const ajvKeywords = require("ajv-keywords");
 
   const ajv = new Ajv({
@@ -46,13 +48,13 @@ const getAjv = memoize(() => {
     "patternRequired",
   ]);
 
-// Custom keywords
+  // Custom keywords
   addAbsolutePathKeyword(ajv);
+  addUndefinedAsNullKeyword(ajv);
 
   return ajv;
 });
 
-
 /** @typedef {import("json-schema").JSONSchema4} JSONSchema4 */
 /** @typedef {import("json-schema").JSONSchema6} JSONSchema6 */
 /** @typedef {import("json-schema").JSONSchema7} JSONSchema7 */
@@ -65,6 +67,7 @@ const getAjv = memoize(() => {
  * @property {boolean=} formatExclusiveMinimum
  * @property {boolean=} formatExclusiveMaximum
  * @property {string=} link
+ * @property {boolean=} undefinedAsNull
  */
 
 /** @typedef {(JSONSchema4 | JSONSchema6 | JSONSchema7) & Extend} Schema */
diff --git a/test/__snapshots__/index.test.js.snap b/test/__snapshots__/index.test.js.snap
index 9ab643e..96d966e 100644
--- a/test/__snapshots__/index.test.js.snap
+++ b/test/__snapshots__/index.test.js.snap
@@ -70,7 +70,7 @@ exports[`Validation should fail validation for absolute path 2`] = `
 exports[`Validation should fail validation for additional key on root 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration has an unknown property 'postcss'. These properties are valid:
-   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2? }"
+   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2?, enumKeywordAndUndefined?, arrayStringAndEnum?, arrayStringAndEnumAndNoUndefined? }"
 `;
 
 exports[`Validation should fail validation for additionalItems #2 1`] = `
@@ -412,6 +412,36 @@ exports[`Validation should fail validation for array with empty items, empty add
    [any, ...]"
 `;
 
+exports[`Validation should fail validation for array with enum and undefined #2 1`] = `
+"Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
+ - configuration.arrayStringAndEnum[3] should be one of these:
+   0 | false | \\"\\" | null | undefined | non-empty string
+   Details:
+    * configuration.arrayStringAndEnum[3] should be one of these:
+      0 | false | \\"\\" | null | undefined
+    * configuration.arrayStringAndEnum[3] should be a non-empty string."
+`;
+
+exports[`Validation should fail validation for array with enum and undefined #3 1`] = `
+"Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
+ - configuration.arrayStringAndEnumAndNoUndefined[2] should be one of these:
+   0 | false | \\"\\" | null | non-empty string
+   Details:
+    * configuration.arrayStringAndEnumAndNoUndefined[2] should be one of these:
+      0 | false | \\"\\" | null
+    * configuration.arrayStringAndEnumAndNoUndefined[2] should be a non-empty string."
+`;
+
+exports[`Validation should fail validation for array with enum and undefined 1`] = `
+"Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
+ - configuration.arrayStringAndEnum[2] should be one of these:
+   0 | false | \\"\\" | null | undefined | non-empty string
+   Details:
+    * configuration.arrayStringAndEnum[2] should be one of these:
+      0 | false | \\"\\" | null | undefined
+    * configuration.arrayStringAndEnum[2] should be a non-empty string."
+`;
+
 exports[`Validation should fail validation for array with items with true 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration.itemsTrue should be an array:
@@ -738,7 +768,7 @@ exports[`Validation should fail validation for formatMinimum 1`] = `
 exports[`Validation should fail validation for holey array 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration[1] should be an object:
-   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2? }"
+   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2?, enumKeywordAndUndefined?, arrayStringAndEnum?, arrayStringAndEnumAndNoUndefined? }"
 `;
 
 exports[`Validation should fail validation for if/then/else #2 1`] = `
@@ -1354,7 +1384,7 @@ exports[`Validation should fail validation for not string 1`] = `
 exports[`Validation should fail validation for null configuration 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration should be an object:
-   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2? }"
+   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2?, enumKeywordAndUndefined?, arrayStringAndEnum?, arrayStringAndEnumAndNoUndefined? }"
 `;
 
 exports[`Validation should fail validation for null type 1`] = `
@@ -1677,7 +1707,7 @@ exports[`Validation should fail validation for patternRequired without object ty
 exports[`Validation should fail validation for postFormatter #1 1`] = `
 "Invalid configuration object. Webpack has been initialized using a configuration object that does not match the API schema.
  - configuration has an unknown property 'minify'. These properties are valid:
-   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2? }
+   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2?, enumKeywordAndUndefined?, arrayStringAndEnum?, arrayStringAndEnumAndNoUndefined? }
    For typos: please correct them.
    For loader options: webpack >= v2.0.0 no longer allows custom properties in configuration.
      Loaders should be updated to allow passing options via loader options in module.rules.
@@ -1701,7 +1731,7 @@ exports[`Validation should fail validation for postFormatter #2 1`] = `
 exports[`Validation should fail validation for postFormatter 1`] = `
 "Invalid configuration object. Webpack has been initialized using a configuration object that does not match the API schema.
  - configuration has an unknown property 'debug'. These properties are valid:
-   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2? }
+   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2?, enumKeywordAndUndefined?, arrayStringAndEnum?, arrayStringAndEnumAndNoUndefined? }
    The 'debug' property was removed in webpack 2.0.0.
    Loaders should be updated to allow passing this option via loader options in module.rules.
    Until loaders are updated one can use the LoaderOptionsPlugin to switch loaders into debug mode:
@@ -1825,7 +1855,7 @@ exports[`Validation should fail validation for terser-webpack-plugin name 1`] =
 exports[`Validation should fail validation for undefined configuration 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration should be an object:
-   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2? }"
+   object { amd?, bail?, cache?, context?, dependencies?, devServer?, stringKeywordWithLink?, devtool?, entry?, externals?, loader?, mode?, module?, name?, node?, optimization?, output?, parallelism?, performance?, plugins?, profile?, recordsInputPath?, recordsOutputPath?, recordsPath?, resolve?, resolveLoader?, serve?, stats?, target?, watch?, watchOptions?, minLengthOne?, minLengthTwo?, integerType?, nullType?, allOfRef?, customObject?, objectType?, anyOfKeyword?, nestedArrayWithoutItems?, nestedObjectWithoutItems?, arrayType?, arrayType2?, multipleTypes?, zeroMaxItems?, multipleContains?, multipleContains2?, exclusiveMinimumKeyword?, exclusiveMaximumKeyword?, uniqueItemsKeyword?, minPropertiesKeyword?, maxPropertiesKeyword?, requiredKeyword?, requiredKeywordWithAdditionalProperties?, enumKeyword?, formatMinimumKeyword?, formatMaximumKeyword?, formatExclusiveMinimumKeyword?, formatExclusiveMaximumKeyword?, formatMinMaxExclusiveMinKeyword?, formatMinMaxExclusiveMaxKeyword?, minItemsKeyword?, maxItemsKeyword?, itemsKeyword?, itemsKeyword2?, additionalItemsKeyword?, additionalItemsKeyword2?, additionalItemsKeyword3?, additionalItemsKeyword4?, propertiesKeyword?, patternPropertiesKeyword?, patternPropertiesKeyword2?, arrayWithOnlyNumber?, onlyRequired?, dependenciesKeyword?, dependenciesKeyword2?, patternRequiredKeyword?, patternRequiredKeyword2?, onlyProperties?, onlyProperties2?, onlyItems?, onlyItems2?, onlyAdditionalItems?, booleanType?, additionalPropertiesKeyword?, additionalPropertiesKeyword2?, propertyNamesKeyword?, constKeyword?, constKeyword2?, ifThenElseKeyword?, ifThenElseKeyword2?, stringKeyword?, arrayKeyword?, arrayKeyword2?, arrayKeyword3?, arrayKeyword4?, arrayKeyword5?, arrayKeyword6?, arrayKeyword7?, arrayKeyword8?, arrayKeyword9?, arrayKeyword10?, arrayKeyword11?, arrayKeyword12?, arrayKeyword13?, arrayKeyword14?, arrayKeyword15?, arrayKeyword16?, arrayKeyword17?, arrayKeyword18?, arrayKeyword19?, recursion?, extending?, longString?, integerEqualsTo5?, integerWithMinimum?, integerNotWithMinimum?, integerWithNotMinMax?, integerWithExclusiveMinimum?, integerWithExclusiveMaximum?, integerNotZero?, integerZero?, numberWithMinimum?, multipleOfProp?, notMultipleOf?, stringWithMinAndMaxLength?, strictFormat?, strictFormat2?, uniqueItemsProp?, numberAndDescription?, oneOfnumberAndDescriptionAndArray?, maxPropertiesAndMinProperties?, objectTest?, objectTest2?, objectTest3?, objectTest4?, objectTest5?, objectTest6?, objectTest7?, objectTest8?, objectTest9?, stringWithEmptyPattern?, likeArray?, arrayWithEmptyItemsAndEmptyAdditionalItemsAndEmptyContains?, numberWithoutType?, numberWithoutType2?, stringWithoutType?, arrayWithoutType?, additionalItemsFalse?, requiredWithoutType?, dependenciesWithoutType?, propertyNamesWithoutType?, patternRequiredWithoutType?, additionalPropertiesWithoutType?, maxPropertiesWithoutType?, justAnObject?, arrayWithAbsolutePath?, allOfKeyword?, enumWithDescription?, constWithDescription?, itemsTrue?, emptyConst?, oneConst?, constWithEmptyString?, refAndAnyOf?, additionalPropertiesInsideOneOf?, additionalPropertiesInsideOneOf2?, singleContainsItems?, objectWithPropertyDependency?, objectWithPropertyDependency2?, objectWithPropertyDependency3?, objectWithPropertyDependency4?, oneOfWithIf?, constWithArrayNotation?, constWithObjectNotation?, additionalItemsWithoutType?, additionalItemsWithoutType2?, additionalItemsWithoutType3?, containsAndAdditionalItems?, containsInsideItem?, emptyObject?, nonEmptyObject?, nonEmptyObject2?, notEnum?, notConst?, notNumber?, notInteger?, notString?, notBoolean?, notArray?, notObject?, notNull?, notNotNull?, NotNotNotNull?, notMultipleTypes?, notMaxItemsArray?, noTypeLikeNumberMinimum?, noTypeLikeNumberMaximum?, noTypeLikeNumberExclusiveMinimum?, noTypeLikeNumberExclusiveMaximum?, minimumWithTypeNumber?, maximumWithTypeNumber?, exclusiveMinimumWithTypeNumber?, exclusiveMaximumWithTypeNumber?, noTypeLikeNumberMultipleOf?, multipleOfWithNumberType?, noTypeLikeStringMinLength?, noTypeLikeStringMaxLength?, stringWithMinLength?, stringWithMaxLength?, noTypeLikeStringPattern?, patternWithStringType?, noTypeLikeStringFormat?, stringWithFormat?, noTypeLikeStringFormatMaximum?, stringWithFormatMaximum?, multipleInstanceof?, noTypeLikeObjectPatternRequired?, objectWithPatternRequired?, noTypeLikeStringMinLength1?, noTypeLikeArrayMinItems?, noTypeLikeArrayMinItems1?, arrayWithMinItems?, noTypeMinProperties?, noTypeMinProperties1?, objectMinProperties?, noTypeLikeArrayMaxItems?, arrayMaxItems?, noTypeLikeObjectMaxProperties?, objectMaxProperties?, noTypeLikeArrayUniqueItems?, arrayWithUniqueItems?, noTypeLikeArrayAdditionalItems?, arrayWithAdditionalItems?, noTypeLikeArrayContains?, arrayWithContains?, anyOfNoTypeInItem?, oneOfNoTypeInItem?, noTypeLikeObjectPropertyNames?, objectPropertyNames?, noTypeLikeObjectDependencies?, objectWithDependencies?, noTypeLikeObjectAdditionalProperties?, noTypeLikeObjectRequired?, dollarData?, dollarData2?, enumNested?, testAbsolutePath?, notEmptyString?, notEmptyString2?, emptyString?, emptyString2?, enumKeywordAndUndefined?, arrayStringAndEnum?, arrayStringAndEnumAndNoUndefined? }"
 `;
 
 exports[`Validation should fail validation for uniqueItems #2 1`] = `
diff --git a/test/fixtures/schema.json b/test/fixtures/schema.json
index 9959144..20be001 100644
--- a/test/fixtures/schema.json
+++ b/test/fixtures/schema.json
@@ -3786,6 +3786,42 @@
     "emptyString2": {
       "maxLength": 0,
       "type": "string"
+    },
+    "enumKeywordAndUndefined": {
+      "undefinedAsNull": true,
+      "enum": [ 0, false, "", null ]
+    },
+    "arrayStringAndEnum": {
+      "description": "References to other configurations to depend on.",
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "undefinedAsNull": true,
+            "enum": [ 0, false, "", null ]
+          },
+          {
+            "type": "string",
+            "minLength": 1
+          }
+        ]
+      }
+    },
+    "arrayStringAndEnumAndNoUndefined": {
+      "description": "References to other configurations to depend on.",
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "undefinedAsNull": false,
+            "enum": [ 0, false, "", null ]
+          },
+          {
+            "type": "string",
+            "minLength": 1
+          }
+        ]
+      }
     }
   }
 }
diff --git a/test/index.test.js b/test/index.test.js
index fa24356..159c2d9 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -2971,4 +2971,53 @@ describe("Validation", () => {
     {},
     webpackSchema
   );
+
+  createSuccessTestCase("enum with undefined", {
+    // eslint-disable-next-line no-undefined
+    enumKeywordAndUndefined: undefined,
+  });
+
+  createSuccessTestCase("enum with undefined #2", {
+    enumKeywordAndUndefined: 0,
+  });
+
+  createSuccessTestCase("array with enum and undefined", {
+    arrayStringAndEnum: ["a", "b", "c"],
+  });
+
+  createSuccessTestCase("array with enum and undefined #2", {
+    // eslint-disable-next-line no-undefined
+    arrayStringAndEnum: [undefined, false, undefined, 0, "test", undefined],
+  });
+
+  createSuccessTestCase("array with enum and undefined #3", {
+    // eslint-disable-next-line no-undefined
+    arrayStringAndEnum: [undefined, null, false, 0, ""],
+  });
+
+  createFailedTestCase(
+    "array with enum and undefined",
+    {
+      arrayStringAndEnum: ["foo", "bar", 1],
+    },
+    (msg) => expect(msg).toMatchSnapshot()
+  );
+
+  createFailedTestCase(
+    "array with enum and undefined #2",
+    {
+      // eslint-disable-next-line no-undefined
+      arrayStringAndEnum: ["foo", "bar", undefined, 1],
+    },
+    (msg) => expect(msg).toMatchSnapshot()
+  );
+
+  createFailedTestCase(
+    "array with enum and undefined #3",
+    {
+      // eslint-disable-next-line no-undefined
+      arrayStringAndEnumAndNoUndefined: ["foo", "bar", undefined],
+    },
+    (msg) => expect(msg).toMatchSnapshot()
+  );
 });