feat(generator): allow plugins to modify how configs are extracted

packages/@vue/cli-plugin-eslint/ui.js

@@ -11,6 +11,7 @@ module.exports = api => {
       eslint: {
         js: ['.eslintrc.js'],
         json: ['.eslintrc', '.eslintrc.json'],
+        yaml: ['.eslintrc.yaml', '.eslintrc.yml'],
         package: 'eslintConfig'
       },
       vue: {

packages/@vue/cli-plugin-pwa/lib/HtmlPwaPlugin.js

@@ -22,7 +22,7 @@ module.exports = class HtmlPwaPlugin {
   constructor (options = {}) {
     const iconPaths = Object.assign({}, defaultIconPaths, options.iconPaths)
     delete options.iconPaths
-    this.options = Object.assign({iconPaths: iconPaths}, defaults, options)
+    this.options = Object.assign({ iconPaths: iconPaths }, defaults, options)
   }
 
   apply (compiler) {

packages/@vue/cli/__tests__/Generator.spec.js

@@ -510,6 +510,98 @@ test('api: addEntryDuplicateNonIdentifierInjection', async () => {
   expect(fs.readFileSync('/main.js', 'utf-8')).toMatch(/{\s+p: p\(\),\s+baz,\s+render/)
 })
 
+test('api: addConfigTransform', async () => {
+  const configs = {
+    fooConfig: {
+      bar: 42
+    }
+  }
+
+  const generator = new Generator('/', { plugins: [
+    {
+      id: 'test',
+      apply: api => {
+        api.addConfigTransform('fooConfig', {
+          file: {
+            json: ['foo.config.json']
+          }
+        })
+        api.extendPackage(configs)
+      }
+    }
+  ] })
+
+  await generator.generate({
+    extractConfigFiles: true
+  })
+
+  const json = v => JSON.stringify(v, null, 2)
+  expect(fs.readFileSync('/foo.config.json', 'utf-8')).toMatch(json(configs.fooConfig))
+  expect(generator.pkg).not.toHaveProperty('fooConfig')
+})
+
+test('api: addConfigTransform (multiple)', async () => {
+  const configs = {
+    bazConfig: {
+      field: 2501
+    }
+  }
+
+  const generator = new Generator('/', { plugins: [
+    {
+      id: 'test',
+      apply: api => {
+        api.addConfigTransform('bazConfig', {
+          file: {
+            js: ['.bazrc.js'],
+            json: ['.bazrc', 'baz.config.json']
+          }
+        })
+        api.extendPackage(configs)
+      }
+    }
+  ] })
+
+  await generator.generate({
+    extractConfigFiles: true
+  })
+
+  const js = v => `module.exports = ${stringifyJS(v, null, 2)}`
+  expect(fs.readFileSync('/.bazrc.js', 'utf-8')).toMatch(js(configs.bazConfig))
+  expect(generator.pkg).not.toHaveProperty('bazConfig')
+})
+
+test('api: addConfigTransform transform vue warn', async () => {
+  const configs = {
+    vue: {
+      lintOnSave: true
+    }
+  }
+
+  const generator = new Generator('/', { plugins: [
+    {
+      id: 'test',
+      apply: api => {
+        api.addConfigTransform('vue', {
+          file: {
+            js: ['vue.config.js']
+          }
+        })
+        api.extendPackage(configs)
+      }
+    }
+  ] })
+
+  await generator.generate({
+    extractConfigFiles: true
+  })
+
+  expect(fs.readFileSync('/vue.config.js', 'utf-8')).toMatch('module.exports = {\n  lintOnSave: true\n}')
+  expect(logs.warn.some(([msg]) => {
+    return msg.match(/Reserved config transform 'vue'/)
+  })).toBe(true)
+})
+
 test('extract config files', async () => {
   const configs = {
     vue: {

packages/@vue/cli/lib/ConfigTransform.js

@@ -0,0 +1,65 @@
+const transforms = require('./util/configTransforms')
+
+class ConfigTransform {
+  constructor (options) {
+    this.fileDescriptor = options.file
+  }
+
+  transform (value, checkExisting, files, context) {
+    let file
+    if (checkExisting) {
+      file = this.findFile(files)
+    }
+    if (!file) {
+      file = this.getDefaultFile()
+    }
+    const { type, filename } = file
+
+    const transform = transforms[type]
+
+    let source
+    let existing
+    if (checkExisting) {
+      source = files[filename]
+      if (source) {
+        existing = transform.read({
+          source,
+          filename,
+          context
+        })
+      }
+    }
+
+    const content = transform.write({
+      source,
+      filename,
+      context,
+      value,
+      existing
+    })
+
+    return {
+      filename,
+      content
+    }
+  }
+
+  findFile (files) {
+    for (const type of Object.keys(this.fileDescriptor)) {
+      const descriptors = this.fileDescriptor[type]
+      for (const filename of descriptors) {
+        if (files[filename]) {
+          return { type, filename }
+        }
+      }
+    }
+  }
+
+  getDefaultFile () {
+    const [type] = Object.keys(this.fileDescriptor)
+    const [filename] = this.fileDescriptor[type]
+    return { type, filename }
+  }
+}
+
+module.exports = ConfigTransform

packages/@vue/cli/lib/Generator.js

@@ -3,10 +3,10 @@ const debug = require('debug')
 const GeneratorAPI = require('./GeneratorAPI')
 const sortObject = require('./util/sortObject')
 const writeFileTree = require('./util/writeFileTree')
-const configTransforms = require('./util/configTransforms')
 const normalizeFilePaths = require('./util/normalizeFilePaths')
 const injectImportsAndOptions = require('./util/injectImportsAndOptions')
 const { toShortPluginId, matchesPluginId } = require('@vue/cli-shared-utils')
+const ConfigTransform = require('./ConfigTransform')
 
 const logger = require('@vue/cli-shared-utils/lib/logger')
 const logTypes = {
@@ -17,6 +17,46 @@ const logTypes = {
   error: logger.error
 }
 
+const defaultConfigTransforms = {
+  babel: new ConfigTransform({
+    file: {
+      js: ['babel.config.js']
+    }
+  }),
+  postcss: new ConfigTransform({
+    file: {
+      js: ['.postcssrc.js'],
+      json: ['.postcssrc.json', '.postcssrc'],
+      yaml: ['.postcssrc.yaml', '.postcssrc.yml']
+    }
+  }),
+  eslintConfig: new ConfigTransform({
+    file: {
+      js: ['.eslintrc.js'],
+      json: ['.eslintrc', '.eslintrc.json'],
+      yaml: ['.eslintrc.yaml', '.eslintrc.yml']
+    }
+  }),
+  jest: new ConfigTransform({
+    file: {
+      js: ['jest.config.js']
+    }
+  }),
+  browserslist: new ConfigTransform({
+    file: {
+      lines: ['.browserslistrc']
+    }
+  })
+}
+
+const reservedConfigTransforms = {
+  vue: new ConfigTransform({
+    file: {
+      js: ['vue.config.js']
+    }
+  })
+}
+
 module.exports = class Generator {
   constructor (context, {
     pkg = {},
@@ -32,8 +72,10 @@ module.exports = class Generator {
     this.imports = {}
     this.rootOptions = {}
     this.completeCbs = completeCbs
+    this.configTransforms = {}
+    this.defaultConfigTransforms = defaultConfigTransforms
+    this.reservedConfigTransforms = reservedConfigTransforms
     this.invoking = invoking
-
     // for conflict resolution
     this.depSources = {}
     // virtual file tree
@@ -70,6 +112,11 @@ module.exports = class Generator {
   }
 
   extractConfigFiles (extractAll, checkExisting) {
+    const configTransforms = Object.assign({},
+      defaultConfigTransforms,
+      this.configTransforms,
+      reservedConfigTransforms
+    )
     const extract = key => {
       if (
         configTransforms[key] &&
@@ -78,8 +125,8 @@ module.exports = class Generator {
         !this.originalPkg[key]
       ) {
         const value = this.pkg[key]
-        const transform = configTransforms[key]
-        const res = transform(
+        const configTransform = configTransforms[key]
+        const res = configTransform.transform(
           value,
           checkExisting,
           this.files,

packages/@vue/cli/lib/GeneratorAPI.js

@@ -8,7 +8,8 @@ const isBinary = require('isbinaryfile')
 const yaml = require('yaml-front-matter')
 const mergeDeps = require('./util/mergeDeps')
 const stringifyJS = require('./util/stringifyJS')
-const { getPluginLink, toShortPluginId } = require('@vue/cli-shared-utils')
+const { warn, getPluginLink, toShortPluginId } = require('@vue/cli-shared-utils')
+const ConfigTransform = require('./ConfigTransform')
 
 const isString = val => typeof val === 'string'
 const isFunction = val => typeof val === 'function'
@@ -81,6 +82,38 @@ class GeneratorAPI {
     return this.generator.hasPlugin(id)
   }
 
+  /**
+   * Configure how config files are extracted.
+   *
+   * @param {string} key - Config key in package.json
+   * @param {object} options - Options
+   * @param {object} options.file - File descriptor
+   * Used to search for existing file.
+   * Each key is a file type (possible values: ['js', 'json', 'yaml', 'lines']).
+   * The value is a list of filenames.
+   * Example:
+   * {
+   *   js: ['.eslintrc.js'],
+   *   json: ['.eslintrc.json', '.eslintrc']
+   * }
+   * By default, the first filename will be used to create the config file.
+   */
+  addConfigTransform (key, options) {
+    const hasReserved = Object.keys(this.generator.reservedConfigTransforms).includes(key)
+    if (
+      hasReserved ||
+      !options ||
+      !options.file
+    ) {
+      if (hasReserved) {
+        warn(`Reserved config transform '${key}'`)
+      }
+      return
+    }
+
+    this.generator.configTransforms[key] = new ConfigTransform(options)
+  }
+
   /**
    * Extend the package.json of the project.
    * Nested fields are deep-merged unless `{ merge: false }` is passed.