fix: enable whitelist in exclude function

Author: yyx990803

Diff for: docs/guide/pre-processors.md

@@ -172,6 +172,23 @@ npm install -D babel-core babel-loader
 
 Configuration of Babel can be done via `.babelrc` or `babel-loader` options.
 
+### Excluding node_modules
+
+It is common to have `exclude: /node_modules/` for JS transpilation rules (e.g. `babel-loader`) that apply to `.js` files. Due to the inference change of v15, if you import a Vue SFC inside `node_modules`, its `<script>` part will be excluded from transpilation as well.
+
+In order to ensure JS transpilation is applied to Vue SFCs in `node_modules`, you need to whitelist them by using an exclude function instead:
+
+``` js
+{
+  test: /\.js$/,
+  loader: 'babel-loader',
+  exclude: file => (
+    /node_modules/.test(file) &&
+    !/\.vue\.js/.test(file)
+  )
+}
+```
+
 ## TypeScript
 
 ``` bash

Diff for: docs/migrating.md

@@ -57,6 +57,23 @@ The benefit is that this same rule also applies to plain `*.less` imports from J
 
 v15 also allows using non-serializable options for loaders, which was not possible in previous versions.
 
+### Importing SFCs from Dependencies
+
+It is common to have `exclude: /node_modules/` for JS transpilation rules (e.g. `babel-loader`) that apply to `.js` files. Due to the inference change of v15, if you import a Vue SFC inside `node_modules`, its `<script>` part will be excluded from transpilation as well.
+
+In order to ensure JS transpilation is applied to Vue SFCs in `node_modules`, you need to whitelist them by using an exclude function instead:
+
+``` js
+{
+  test: /\.js$/,
+  loader: 'babel-loader',
+  exclude: file => (
+    /node_modules/.test(file) &&
+    !/\.vue\.js/.test(file)
+  )
+}
+```
+
 ### Template Preprocessing
 
 v14 and below uses [consolidate](https://github.com/tj/consolidate.js/) to compile `<template lang="xxx">`. v15 now applies preprocessing for them using webpack loaders instead.

Diff for: lib/plugin.js

@@ -151,7 +151,7 @@ function cloneRule (rule, normalizedRule) {
       if (resource && parsed.lang == null) {
         return false
       }
-      const fakeResourcePath = `${currentResource.replace(/\.vue$/, '')}.${parsed.lang}`
+      const fakeResourcePath = `${currentResource}.${parsed.lang}`
       if (resource && !resource(fakeResourcePath)) {
         return false
       }