fix(error-messaging): add better error messaging when a transform or …

…transformGroup does not exist (#264)

__tests__/buildPlatform.test.js

@@ -25,7 +25,7 @@ describe('buildPlatform', () => {
   it('should throw if passed a platform that doesn\'t exist', () => {
     expect(
       StyleDictionaryExtended.buildPlatform.bind(test, 'foobar'),
-    ).toThrow('Platform foobar doesn\'t exist');
+    ).toThrow('Platform "foobar" does not exist');
 
     expect(
       function() {
@@ -164,9 +164,15 @@ describe('buildPlatform', () => {
         }
       }
     });
+
+    let err = `
+Unknown transformGroup "bar" found in platform "foo":
+"bar" does not match the name of a registered transformGroup.
+`;
+
     expect(
       StyleDictionaryExtended.buildPlatform.bind(StyleDictionaryExtended, 'foo'),
-    ).toThrow('transformGroup bar doesn\'t exist');
+    ).toThrow(err);
   });
 
 });

__tests__/transform/config.test.js

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with
+ * the License. A copy of the License is located at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+ * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ */
+
+var transformConfig = require('../../lib/transform/config');
+
+const dictionary = {
+  transformGroup: {
+    fooTransformGroup: ['barTransform']
+  },
+  transform: {
+    fooTransform: {
+      type: 'attribute',
+      transformer: function() {
+        return {bar: 'foo'}
+      }
+    }
+  }
+};
+
+describe('transform', () => {
+  describe('config', () => {
+    it('Emits error when called with a transformGroup that does not exist in the dictionary', () => {
+      const noTransformGroupCfg = {
+        transformGroup: 'barTransformGroup'
+      };
+
+      let err = `
+Unknown transformGroup "barTransformGroup" found in platform "test":
+"barTransformGroup" does not match the name of a registered transformGroup.
+`;
+
+      expect(
+        transformConfig.bind(null, noTransformGroupCfg, dictionary, 'test')
+      ).toThrow(err);
+    });
+
+    it('Emits errors when called with a transform that does not exist', () => {
+      const noTransformCfg = {
+        transforms: ['fooTransform', 'barTransform', 'bazTransform']
+      };
+
+      let err = `
+Unknown transforms "barTransform", "bazTransform" found in platform "test":
+None of "barTransform", "bazTransform" match the name of a registered transform.
+`;
+
+      expect(
+        transformConfig.bind(null, noTransformCfg, dictionary, 'test')
+      ).toThrow(err);
+    });
+  });
+});

lib/buildPlatform.js

@@ -43,12 +43,12 @@ function buildPlatform(platform) {
   console.log('\n' + platform);
 
   if (!this.options || !_.has(this.options.platforms, platform)) {
-    throw new Error('Platform ' + platform + ' doesn\'t exist');
+    throw new Error(`Platform "${platform}" does not exist`);
   }
 
   var properties;
   // We don't want to mutate the original object
-  var platformConfig = transformConfig(this.options.platforms[platform], this);
+  var platformConfig = transformConfig(this.options.platforms[platform], this, platform);
 
   // We need to transform the object before we resolve the
   // variable names because if a value contains concatenated

lib/cleanPlatform.js

@@ -38,7 +38,7 @@ function cleanPlatform(platform) {
 
   var properties;
   // We don't want to mutate the original object
-  var platformConfig = transformConfig(this.options.platforms[platform], this);
+  var platformConfig = transformConfig(this.options.platforms[platform], this, platform);
 
   // We need to transform the object before we resolve the
   // variable names because if a value contains concatenated

lib/exportPlatform.js

@@ -37,7 +37,7 @@ function exportPlatform(platform) {
   }
 
   // We don't want to mutate the original object
-  var platformConfig = transformConfig(this.options.platforms[platform], this);
+  var platformConfig = transformConfig(this.options.platforms[platform], this, platform);
 
   // We need to transform the object before we resolve the
   // variable names because if a value contains concatenated

lib/transform/config.js

@@ -15,6 +15,7 @@ var _     = require('lodash'),
     GroupMessages = require('../utils/groupMessages');
 
 var TEMPLATE_DEPRECATION_WARNINGS = GroupMessages.GROUP.TemplateDeprecationWarnings;
+var MISSING_TRANSFORM_ERRORS = GroupMessages.GROUP.MissingRegisterTransformErrors;
 
 /**
  * Takes a platform config object and returns a new one
@@ -23,9 +24,10 @@ var TEMPLATE_DEPRECATION_WARNINGS = GroupMessages.GROUP.TemplateDeprecationWarni
  * @private
  * @param {Object} config
  * @param {Object} dictionary
+ * @param {Object} platformName (only used for error messaging)
  * @returns {Object}
  */
-function transformConfig(config, dictionary) {
+function transformConfig(config, dictionary, platformName) {
   var to_ret = _.clone(config);
 
   // The platform can define either a transformGroup or an array
@@ -40,17 +42,48 @@ function transformConfig(config, dictionary) {
     if (dictionary.transformGroup[to_ret.transformGroup]) {
       transforms = dictionary.transformGroup[to_ret.transformGroup];
     } else {
-      throw new Error('transformGroup ' + to_ret.transformGroup + ' doesn\'t exist');
+      let err = `
+Unknown transformGroup "${to_ret.transformGroup}" found in platform "${platformName}":
+"${to_ret.transformGroup}" does not match the name of a registered transformGroup.
+`;
+      throw new Error(err);
     }
   }
 
   // Transforms are an array of strings that map to functions on
   // the StyleDictionary module. We need to map the strings to
   // the actual functions.
   to_ret.transforms = _.map(transforms, function(name) {
+    if(!dictionary.transform[name]) {
+      GroupMessages.add(
+        MISSING_TRANSFORM_ERRORS,
+        `"${name}"`
+      );
+    }
     return dictionary.transform[name];
   });
 
+  let missingTransformCount = GroupMessages.count(MISSING_TRANSFORM_ERRORS);
+  if(missingTransformCount > 0) {
+    var transform_warnings = GroupMessages.flush(MISSING_TRANSFORM_ERRORS).join(', ');
+    let err;
+
+    if(missingTransformCount==1) {
+      err = `
+Unknown transform ${transform_warnings} found in platform "${platformName}":
+${transform_warnings} does not match the name of a registered transform.
+`;
+    }
+    else {
+        err = `
+Unknown transforms ${transform_warnings} found in platform "${platformName}":
+None of ${transform_warnings} match the name of a registered transform.
+`;
+    }
+
+    throw new Error(err);
+  }
+
   to_ret.files = _.map(config.files, function(file) {
     const ext = {};
     if (file.filter) {

lib/utils/groupMessages.js

@@ -19,6 +19,7 @@ var GroupMessages = {
     TemplateDeprecationWarnings: 'Template Deprecation Warnings',
     RegisterTemplateDeprecationWarnings: 'Register Template Deprecation Warnings',
     SassMapFormatDeprecationWarnings: 'Sass Map Format Deprecation Warnings',
+    MissingRegisterTransformErrors: 'Missing Register Transform Errors',
   },
 
   flush: function (messageGroup) {