refactor: use babel overrides to transpile babel runtime helpers

As recommended in babel/babel#9903. Get rid of the module-resolver plugin, may fix #3928. Seems to have fixed #4742 as well.
vuejs · haoqunjiang · Nov 4, 2019 · Oct 30, 2019 · Oct 31, 2019 · Oct 31, 2019
commit c6cd32213f2eadc4ea305d72a7974b7388326473
diff --git a/packages/@vue/babel-preset-app/index.js b/packages/@vue/babel-preset-app/index.js
@@ -183,24 +183,25 @@ module.exports = (context, options = {}) => {
     absoluteRuntime
   }])
 
-  // use @babel/runtime-corejs3 so that helpers that need polyfillable APIs will reference core-js instead.
-  // if useBuiltIns is not set to 'usage', then it means users would take care of the polyfills on their own,
-  // i.e., core-js 3 is no longer needed.
-  // this extra plugin can be removed once one of the two issues resolves:
-  // https://github.com/babel/babel/issues/7597
-  // https://github.com/babel/babel/issues/9903
-  if (useBuiltIns === 'usage' && !process.env.VUE_CLI_MODERN_BUILD) {
-    const runtimeCoreJs3Path = path.dirname(require.resolve('@babel/runtime-corejs3/package.json'))
-    plugins.push([require('babel-plugin-module-resolver'), {
-      alias: {
-        '@babel/runtime': '@babel/runtime-corejs3',
-        [runtimePath]: runtimeCoreJs3Path
-      }
-    }])
-  }
-
   return {
-    presets,
-    plugins
+    overrides: [{
+      exclude: [/@babel\/runtime/, /core-js/],
+      presets,
+      plugins
+    }, {
+      // there are some untranspiled code in @babel/runtime
+      // https://github.com/babel/babel/issues/9903
+      include: [/@babel\/runtime/],
+      presets: [
+        [require('@babel/preset-env'), {
+          useBuiltIns,
+          corejs: 3
+        }]
+      ]
+    }]
   }
 }
+
+// a special flag to tell @vue/cli-plugin-babel to include @babel/runtime for transpilation
+// otherwise the above `include` option won't take effect
+process.env.VUE_CLI_TRANSPILE_BABEL_RUNTIME = true
diff --git a/packages/@vue/babel-preset-app/package.json b/packages/@vue/babel-preset-app/package.json
@@ -31,10 +31,8 @@
     "@babel/plugin-transform-runtime": "^7.6.2",
     "@babel/preset-env": "^7.6.3",
     "@babel/runtime": "^7.6.3",
-    "@babel/runtime-corejs3": "^7.6.3",
     "@vue/babel-preset-jsx": "^1.1.1",
     "babel-plugin-dynamic-import-node": "^2.2.0",
-    "babel-plugin-module-resolver": "^3.2.0",
     "core-js": "^3.3.2",
     "core-js-compat": "^3.3.2"
   }

diff --git a/packages/@vue/cli-plugin-babel/index.js b/packages/@vue/cli-plugin-babel/index.js
@@ -1,4 +1,5 @@
 const path = require('path')
+const babel = require('@babel/core')
 const { isWindows } = require('@vue/cli-shared-utils')
 
 function genTranspileDepRegex (transpileDependencies) {
@@ -17,9 +18,14 @@ function genTranspileDepRegex (transpileDependencies) {
 
 module.exports = (api, options) => {
   const useThreads = process.env.NODE_ENV === 'production' && !!options.parallel
-  const cliServicePath = require('path').dirname(require.resolve('@vue/cli-service'))
+  const cliServicePath = path.dirname(require.resolve('@vue/cli-service'))
   const transpileDepRegex = genTranspileDepRegex(options.transpileDependencies)
 
+  // try to load the project babel config;
+  // if the default preset is used,
+  // there will be a VUE_CLI_TRANSPILE_BABEL_RUNTIME env var set.
+  babel.loadPartialConfig()
+
   api.chainWebpack(webpackConfig => {
     webpackConfig.resolveLoader.modules.prepend(path.join(__dirname, 'node_modules'))
 
@@ -36,6 +42,15 @@ module.exports = (api, options) => {
             if (filepath.startsWith(cliServicePath)) {
               return true
             }
+
+            // only include @babel/runtime when the @vue/babel-preset-app preset is used
+            if (
+              process.env.VUE_CLI_TRANSPILE_BABEL_RUNTIME &&
+              filepath.includes(path.join('@babel', 'runtime'))
+            ) {
+              return false
+            }
+
             // check if this is something the user explicitly wants to transpile
             if (transpileDepRegex && transpileDepRegex.test(filepath)) {
               return false