feat: package.json: vuePlugins.resolveFrom option, closes #1815

Author: Guillaume Chau

docs/guide/plugins-and-presets.md

@@ -61,6 +61,20 @@ vue add vuex
 
 If a plugin is already installed, you can skip the installation and only invoke its generator with the `vue invoke` command. The command takes the same arguments as `vue add`.
 
+::: tip
+If for some reason your plugins are listed in a `package.json` file other than the one located in your project, you can set the `vuePlugins.resolveFrom` option in the project `package.json` with the path to the folder containing the other `package.json` file.
+
+For example, if you have a `.config/package.json` file:
+
+```json
+{
+  "vuePlugins": {
+    "resolveFrom": ".config"
+  }
+}
+```
+:::
+
 ## Presets
 
 A Vue CLI preset is a JSON object that contains pre-defined options and plugins for creating a new project so that the user don't have to go through the prompts to select them.

packages/@vue/cli-service/lib/Service.js

@@ -36,11 +36,15 @@ module.exports = class Service {
     }, {})
   }
 
-  resolvePkg (inlinePkg) {
+  resolvePkg (inlinePkg, context = this.context) {
     if (inlinePkg) {
       return inlinePkg
-    } else if (fs.existsSync(path.join(this.context, 'package.json'))) {
-      return readPkg.sync({ cwd: this.context })
+    } else if (fs.existsSync(path.join(context, 'package.json'))) {
+      const pkg = readPkg.sync({ cwd: context })
+      if (pkg.vuePlugins && pkg.vuePlugins.resolveFrom) {
+        return this.resolvePkg(null, path.resolve(context, pkg.vuePlugins.resolveFrom))
+      }
+      return pkg
     } else {
       return {}
     }

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

@@ -1,4 +1,4 @@
-const fs = require('fs')
+const fs = require('fs-extra')
 const path = require('path')
 const execa = require('execa')
 const chalk = require('chalk')
@@ -43,7 +43,11 @@ function getPkg (context) {
   if (!fs.existsSync(pkgPath)) {
     throw new Error(`package.json not found in ${chalk.yellow(context)}`)
   }
-  return loadModule(pkgPath, context, true)
+  const pkg = fs.readJsonSync(pkgPath)
+  if (pkg.vuePlugins && pkg.vuePlugins.resolveFrom) {
+    return getPkg(path.resolve(context, pkg.vuePlugins.resolveFrom))
+  }
+  return pkg
 }
 
 async function invoke (pluginName, options = {}, context = process.cwd()) {