refactor: generator internal tweaks

- avoid hitting the disk again when extracting / extending config files
- normalize paths when reading files before invoking

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

@@ -1,10 +1,10 @@
 const ejs = require('ejs')
-const slash = require('slash')
 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')
 
@@ -82,7 +82,7 @@ module.exports = class Generator {
         const res = transform(
           value,
           checkExisting,
-          this.context
+          this.files
         )
         const { content, filename } = res
         this.files[filename] = content
@@ -141,20 +141,20 @@ module.exports = class Generator {
     for (const middleware of this.fileMiddlewares) {
       await middleware(files, ejs.render)
     }
+
+    // normalize file paths on windows
+    // all paths are converted to use / instead of \
+    normalizeFilePaths(files)
+
+    // handle imports and root option injections
     Object.keys(files).forEach(file => {
-      // normalize paths
-      const normalized = slash(file)
-      if (file !== normalized) {
-        files[normalized] = files[file]
-        delete files[file]
-      }
-      // handle imports and root option injections
-      files[normalized] = injectImportsAndOptions(
-        files[normalized],
-        this.imports[normalized],
-        this.rootOptions[normalized]
+      files[file] = injectImportsAndOptions(
+        files[file],
+        this.imports[file],
+        this.rootOptions[file]
       )
     })
+
     for (const postProcess of this.postProcessFilesCbs) {
       await postProcess(files)
     }

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

@@ -7,8 +7,9 @@ const inquirer = require('inquirer')
 const isBinary = require('isbinaryfile')
 const Generator = require('./Generator')
 const { loadOptions } = require('./options')
-const { installDeps } = require('./util/installDeps')
 const { loadModule } = require('./util/module')
+const { installDeps } = require('./util/installDeps')
+const normalizeFilePaths = require('./util/normalizeFilePaths')
 const {
   log,
   error,
@@ -33,7 +34,7 @@ async function readFiles (context) {
       ? fs.readFileSync(name)
       : fs.readFileSync(name, 'utf-8')
   }
-  return res
+  return normalizeFilePaths(res)
 }
 
 function getPkg (context) {

packages/@vue/cli/lib/util/configTransforms.js

@@ -1,15 +1,12 @@
-const fs = require('fs')
-const path = require('path')
 const extendJSConfig = require('./extendJSConfig')
 const stringifyJS = require('./stringifyJS')
 
 function makeJSTransform (filename) {
-  return function transformToJS (value, checkExisting, context) {
-    const absolutePath = path.resolve(context, filename)
-    if (checkExisting && fs.existsSync(absolutePath)) {
+  return function transformToJS (value, checkExisting, files) {
+    if (checkExisting && files[filename]) {
       return {
         filename,
-        content: extendJSConfig(value, fs.readFileSync(absolutePath, 'utf-8'))
+        content: extendJSConfig(value, files[filename])
       }
     } else {
       return {
@@ -21,11 +18,10 @@ function makeJSTransform (filename) {
 }
 
 function makeJSONTransform (filename) {
-  return function transformToJSON (value, checkExisting, context) {
+  return function transformToJSON (value, checkExisting, files) {
     let existing = {}
-    const absolutePath = path.resolve(context, filename)
-    if (checkExisting && fs.existsSync(absolutePath)) {
-      existing = JSON.parse(fs.readFileSync(absolutePath, 'utf-8'))
+    if (checkExisting && files[filename]) {
+      existing = JSON.parse(files[filename])
     }
     value = Object.assign(existing, value)
     return {
@@ -36,12 +32,12 @@ function makeJSONTransform (filename) {
 }
 
 function makeMutliExtensionJSONTransform (filename, preferJS) {
-  return function transformToMultiExtensions (value, checkExisting, context) {
+  return function transformToMultiExtensions (value, checkExisting, files) {
     function defaultTransform () {
       if (preferJS) {
-        return makeJSTransform(`${filename}.js`)(value, false, context)
+        return makeJSTransform(`${filename}.js`)(value, false, files)
       } else {
-        return makeJSONTransform(filename)(value, false, context)
+        return makeJSONTransform(filename)(value, false, files)
       }
     }
 
@@ -49,17 +45,16 @@ function makeMutliExtensionJSONTransform (filename, preferJS) {
       return defaultTransform()
     }
 
-    const absolutePath = path.resolve(context, filename)
-    if (fs.existsSync(absolutePath)) {
-      return makeJSONTransform(filename)(value, checkExisting, context)
-    } else if (fs.existsSync(`${absolutePath}.json`)) {
-      return makeJSONTransform(`${filename}.json`)(value, checkExisting, context)
-    } else if (fs.existsSync(`${absolutePath}.js`)) {
-      return makeJSTransform(`${filename}.js`)(value, checkExisting, context)
-    } else if (fs.existsSync(`${absolutePath}.yaml`)) {
-      return transformYAML(value, `${filename}.yaml`, fs.readFileSync(`${absolutePath}.yaml`, 'utf-8'))
-    } else if (fs.existsSync(`${absolutePath}.yml`)) {
-      return transformYAML(value, `${filename}.yml`, fs.readFileSync(`${absolutePath}.yml`, 'utf-8'))
+    if (files[filename]) {
+      return makeJSONTransform(filename)(value, checkExisting, files)
+    } else if (files[`${filename}.json`]) {
+      return makeJSONTransform(`${filename}.json`)(value, checkExisting, files)
+    } else if (files[`${filename}.js`]) {
+      return makeJSTransform(`${filename}.js`)(value, checkExisting, files)
+    } else if (files[`${filename}.yaml`]) {
+      return transformYAML(value, `${filename}.yaml`, files[`${filename}.yaml`])
+    } else if (files[`${filename}.yml`]) {
+      return transformYAML(value, `${filename}.yml`, files[`${filename}.yml`])
     } else {
       return defaultTransform()
     }

packages/@vue/cli/lib/util/normalizeFilePaths.js

@@ -0,0 +1,12 @@
+const slash = require('slash')
+
+module.exports = function normalizeFilePaths (files) {
+  Object.keys(files).forEach(file => {
+    const normalized = slash(file)
+    if (file !== normalized) {
+      files[normalized] = files[file]
+      delete files[file]
+    }
+  })
+  return files
+}