Factor out suggestion quoting utility

src/jsutils/__tests__/quotedOrList-test.js

@@ -0,0 +1,40 @@
+/**
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+import { expect } from 'chai';
+import { describe, it } from 'mocha';
+import quotedOrList from '../quotedOrList';
+
+describe('quotedOrList', () => {
+
+  it('Does not accept an empty list', () => {
+    expect(() => quotedOrList([])).to.throw(TypeError);
+  });
+
+  it('Returns single quoted item', () => {
+    expect(quotedOrList([ 'A' ])).to.equal('"A"');
+  });
+
+  it('Returns two item list', () => {
+    expect(quotedOrList([ 'A', 'B' ])).to.equal('"A" or "B"');
+  });
+
+  it('Returns comma separated many item list', () => {
+    expect(quotedOrList([ 'A', 'B', 'C' ])).to.equal('"A", "B", or "C"');
+  });
+
+  it('Limits to five items', () => {
+    expect(
+      quotedOrList([ 'A', 'B', 'C', 'D', 'E', 'F' ])
+    ).to.equal(
+      '"A", "B", "C", "D", or "E"'
+    );
+  });
+
+});

src/jsutils/__tests__/suggestionList-test.js

@@ -9,7 +9,7 @@
 
 import { expect } from 'chai';
 import { describe, it } from 'mocha';
-import { suggestionList } from '../suggestionList';
+import suggestionList from '../suggestionList';
 
 describe('suggestionList', () => {
 

src/jsutils/quotedOrList.js

@@ -0,0 +1,26 @@
+/* @flow */
+/**
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+const MAX_LENGTH = 5;
+
+/**
+ * Given [ A, B, C ] return '"A", "B", or "C"'.
+ */
+export default function quotedOrList(items: Array<string>): string {
+  const selected = items.slice(0, MAX_LENGTH);
+  return selected
+    .map(item => `"${item}"`)
+    .reduce((list, quoted, index) =>
+      list +
+      (selected.length > 2 ? ', ' : ' ') +
+      (index === selected.length - 1 ? 'or ' : '') +
+      quoted
+    );
+}

src/jsutils/suggestionList.js

@@ -12,7 +12,7 @@
  * Given an invalid input string and a list of valid options, returns a filtered
  * list of valid options sorted based on their similarity with the input.
  */
-export function suggestionList(
+export default function suggestionList(
   input: string,
   options: Array<string>
 ): Array<string> {

src/validation/rules/FieldsOnCorrectType.js

@@ -10,7 +10,8 @@
 
 import type { ValidationContext } from '../index';
 import { GraphQLError } from '../../error';
-import { suggestionList } from '../../jsutils/suggestionList';
+import suggestionList from '../../jsutils/suggestionList';
+import quotedOrList from '../../jsutils/quotedOrList';
 import type { Field } from '../../language/ast';
 import type { GraphQLSchema } from '../../type/schema';
 import type { GraphQLOutputType } from '../../type/definition';
@@ -28,13 +29,11 @@ export function undefinedFieldMessage(
   suggestedFieldNames: Array<string>
 ): string {
   let message = `Cannot query field "${fieldName}" on type "${type}".`;
-  const MAX_LENGTH = 5;
   if (suggestedTypeNames.length !== 0) {
-    const suggestions = quotedOrList(suggestedTypeNames.slice(0, MAX_LENGTH));
+    const suggestions = quotedOrList(suggestedTypeNames);
     message += ` Did you mean to use an inline fragment on ${suggestions}?`;
   } else if (suggestedFieldNames.length !== 0) {
-    const suggestions = quotedOrList(suggestedFieldNames.slice(0, MAX_LENGTH));
-    message += ` Did you mean ${suggestions}?`;
+    message += ` Did you mean ${quotedOrList(suggestedFieldNames)}?`;
   }
   return message;
 }
@@ -139,15 +138,3 @@ function getSuggestedFieldNames(
   // Otherwise, must be a Union type, which does not define fields.
   return [];
 }
-
-/**
- * Given [ A, B, C ] return '"A", "B", or "C"'.
- */
-function quotedOrList(items: Array<string>): string {
-  return items.map(item => `"${item}"`).reduce((list, quoted, index) =>
-    list +
-    (items.length > 2 ? ', ' : ' ') +
-    (index === items.length - 1 ? 'or ' : '') +
-    quoted
-  );
-}

src/validation/rules/KnownArgumentNames.js

@@ -12,7 +12,8 @@ import type { ValidationContext } from '../index';
 import { GraphQLError } from '../../error';
 import find from '../../jsutils/find';
 import invariant from '../../jsutils/invariant';
-import { suggestionList } from '../../jsutils/suggestionList';
+import suggestionList from '../../jsutils/suggestionList';
+import quotedOrList from '../../jsutils/quotedOrList';
 import {
   FIELD,
   DIRECTIVE
@@ -29,10 +30,7 @@ export function unknownArgMessage(
   let message = `Unknown argument "${argName}" on field "${fieldName}" of ` +
     `type "${type}".`;
   if (suggestedArgs.length) {
-    const suggestions = suggestedArgs
-      .map(t => `"${t}"`)
-      .join(', ');
-    message += ` Perhaps you meant ${suggestions}?`;
+    message += ` Did you mean ${quotedOrList(suggestedArgs)}?`;
   }
   return message;
 }
@@ -45,10 +43,7 @@ export function unknownDirectiveArgMessage(
   let message =
     `Unknown argument "${argName}" on directive "@${directiveName}".`;
   if (suggestedArgs.length) {
-    const suggestions = suggestedArgs
-      .map(t => `"${t}"`)
-      .join(', ');
-    message += ` Perhaps you meant ${suggestions}?`;
+    message += ` Did you mean ${quotedOrList(suggestedArgs)}?`;
   }
   return message;
 }

src/validation/rules/KnownTypeNames.js

@@ -10,7 +10,8 @@
 
 import type { ValidationContext } from '../index';
 import { GraphQLError } from '../../error';
-import { suggestionList } from '../../jsutils/suggestionList';
+import suggestionList from '../../jsutils/suggestionList';
+import quotedOrList from '../../jsutils/quotedOrList';
 import type { GraphQLType } from '../../type/definition';
 
 
@@ -19,13 +20,8 @@ export function unknownTypeMessage(
   suggestedTypes: Array<string>
 ): string {
   let message = `Unknown type "${type}".`;
-  const MAX_LENGTH = 5;
   if (suggestedTypes.length) {
-    const suggestions = suggestedTypes
-      .slice(0, MAX_LENGTH)
-      .map(t => `"${t}"`)
-      .join(', ');
-    message += ` Perhaps you meant one of the following: ${suggestions}.`;
+    message += ` Did you mean ${quotedOrList(suggestedTypes)}?`;
   }
   return message;
 }