feat(module): improve require

lib/module.js

@@ -9,14 +9,14 @@ import {chainFn, sequence} from './utils'
 const debug = require('debug')('nuxt:module')
 
 class Module {
-  constructor (nuxt) {
+  constructor(nuxt) {
     this.nuxt = nuxt
     this.options = nuxt.options
-    this.modules = []
+    this.requiredModules = []
     this.initing = this.ready()
   }
 
-  async ready () {
+  async ready() {
     if (this.initing) {
       await this.initing
       return this
@@ -26,7 +26,7 @@ class Module {
     return this
   }
 
-  addVendor (vendor) {
+  addVendor(vendor) {
     /* istanbul ignore if */
     if (!vendor) {
       return
@@ -34,7 +34,7 @@ class Module {
     this.options.build.vendor = uniq(this.options.build.vendor.concat(vendor))
   }
 
-  addTemplate (template) {
+  addTemplate(template) {
     /* istanbul ignore if */
     if (!template) {
       return
@@ -60,7 +60,7 @@ class Module {
     return templateObj
   }
 
-  addPlugin (template) {
+  addPlugin(template) {
     const {dst} = this.addTemplate(template)
     // Add to nuxt plugins
     this.options.plugins.push({
@@ -69,27 +69,24 @@ class Module {
     })
   }
 
-  addServerMiddleware (middleware) {
+  addServerMiddleware(middleware) {
     this.options.serverMiddleware.push(middleware)
   }
 
-  extendBuild (fn) {
+  extendBuild(fn) {
     this.options.build.extend = chainFn(this.options.build.extend, fn)
   }
 
-  extendRoutes (fn) {
+  extendRoutes(fn) {
     this.options.router.extendRoutes = chainFn(this.options.router.extendRoutes, fn)
   }
 
-  requireModule (moduleOpts) {
-    if (this.modules.indexOf(moduleOpts) !== -1 || this.modules.indexOf(moduleOpts.src) !== -1) {
-      return false
-    }
-    this.modules.push(moduleOpts.src || moduleOpts)
-    return this.addModule(moduleOpts)
+  requireModule(moduleOpts) {
+    // Require once
+    return this.addModule(moduleOpts, true)
   }
 
-  addModule (moduleOpts) {
+  addModule(moduleOpts, requireOnce) {
     /* istanbul ignore if */
     if (!moduleOpts) {
       return
@@ -129,6 +126,19 @@ class Module {
       console.error(`[nuxt] Module [${originalSrc}] should export a function`)
       process.exit(1)
     }
+    // Module meta
+    if (!module.meta) {
+      module.meta = {}
+    }
+    if (module.meta.name) {
+      const alreadyRequired = this.requiredModules.indexOf(module.meta.name) !== -1
+      if (requireOnce && alreadyRequired) {
+        return
+      }
+      if (!alreadyRequired) {
+        this.requiredModules.push(module.meta.name)
+      }
+    }
     // Call module with `this` context and pass options
     return new Promise((resolve, reject) => {
       const result = module.call(this, options, err => {