task(helpers): Abstract helpers and remove duplicates

packages/@vuetify/cli-plugin-utils/index.js

@@ -67,7 +67,7 @@ function generatePreset (api, preset, onCreateComplete) {
   const file = 'src/plugins/vuetify.js'
   const plugin = api.resolve(file)
 
-  if (!fs.existsSync(plugin)) {
+  if (!fileExists(api, plugin)) {
     console.warn('Unable to locate `vuetify.js` plugin file in `src/plugins`.')
 
     return
@@ -104,11 +104,49 @@ function mergeSassVariables (opt, file) {
   return opt
 }
 
+// Resolve the supplied file
+function resolve(file) {
+  return path.resolve(__dirname, file);
+}
+
+// Update Babel config file with supplied callback
+function updateBabelConfig(api, callback) {
+  let config, configPath;
+
+  const rcPath = api.resolve("./babel.config.js");
+  const pkgPath = api.resolve("./package.json");
+  if (fileExists(api, rcPath)) {
+    configPath = rcPath;
+    config = callback(require(rcPath));
+  } else if (fileExists(api, pkgPath)) {
+    configPath = pkgPath;
+    config = JSON.parse(fs.readFileSync(pkgPath, { encoding: "utf8" }));
+
+    if (config.babel) {
+      config.babel = callback(config.babel);
+    } else {
+      // TODO: error handling here?
+    }
+  }
+
+  if (configPath) {
+    const moduleExports = configPath !== pkgPath ? "module.exports = " : "";
+
+    fs.writeFileSync(
+      configPath,
+      `${moduleExports}${JSON.stringify(config, null, 2)}`,
+      { encoding: "utf8" }
+    );
+  } else {
+    // TODO: handle if babel config doesn't exist
+  }
+}
+
 // Update local file with supplied callback
 function updateFile (api, file, callback) {
   const { EOL } = require('os')
   file = api.resolve(file)
-  let content = fs.existsSync(file)
+  let content = fileExists(api, file)
     ? fs.readFileSync(file, { encoding: 'utf8' })
     : ''
 
@@ -189,6 +227,8 @@ module.exports = {
   injectHtmlLink,
   injectSassVariables,
   mergeSassVariables,
+  resolve,
+  updateBabelConfig,
   updateFile,
   updateVuetifyObject,
   VuetifyPresetGenerator,

packages/vue-cli-plugin-vuetify/generator/tools/fonts.js

@@ -1,3 +1,5 @@
+const { updateFile } = require("@vuetify/cli-plugin-utils")
+
 const helpers = require('./helpers')
 const fonts = {
   mdi: {
@@ -52,7 +54,7 @@ function addImports (api, iconFont) {
 }
 
 function addLinks (api, iconFont) {
-  helpers.updateFile(api, './public/index.html', lines => {
+  updateFile(api, './public/index.html', lines => {
     const lastLink = lines.reverse().findIndex(line => line.match(/^\s*<\/head>/))
 
     lines.splice(lastLink + 1, 0, `    ${fonts.roboto.link}`)

packages/vue-cli-plugin-vuetify/generator/tools/helpers.js

@@ -32,18 +32,6 @@ function updateBabelConfig (api, callback) {
   }
 }
 
-function updateFile (api, file, callback) {
-  file = api.resolve(file)
-  let content = fs.existsSync(file)
-    ? fs.readFileSync(file, { encoding: 'utf8' })
-    : ''
-
-  content = callback(content.split(/\r?\n/g)).join('\n')
-
-  fs.writeFileSync(file, content, { encoding: 'utf8' })
-}
-
 module.exports = {
   updateBabelConfig,
-  updateFile,
 }

packages/vue-cli-plugin-vuetify/generator/tools/polyfill.js

@@ -1,6 +1,8 @@
 const helpers = require('./helpers')
 const fs = require('fs')
 
+const { updateFile } = require("@vuetify/cli-plugin-utils")
+
 function addDependencies (api) {
   api.extendPackage({
     dependencies: {
@@ -55,7 +57,7 @@ function updateBrowsersList (api) {
       { encoding: 'utf8' },
     )
   } else {
-    helpers.updateFile(api, './.browserslistrc', lines => {
+    updateFile(api, './.browserslistrc', lines => {
       if (!lines.length) {
         return [
           '> 1%',

packages/vue-cli-plugin-vuetify/generator/tools/vuetify.js

@@ -2,6 +2,8 @@
 const fs = require('fs')
 const helpers = require('./helpers')
 
+const { updateFile } = require("@vuetify/cli-plugin-utils")
+
 function addDependencies (api) {
   api.extendPackage({
     dependencies: {
@@ -53,7 +55,7 @@ function addImports (api) {
 }
 
 function setHtmlLang (api, locale) {
-  helpers.updateFile(api, './public/index.html', lines => {
+  updateFile(api, './public/index.html', lines => {
     const htmlIndex = lines.findIndex(line => line.match(/<html\s+(.+\s+)?lang=[^\s>]+(\s|>)/))
 
     if (htmlIndex !== -1) {