perf: improve CLI startup performance

Author: yyx990803

packages/@vue/cli-shared-utils/lib/request.js

@@ -1,7 +1,7 @@
-const request = require('request-promise-native')
-
 exports.request = {
   get (uri) {
+    // lazy require
+    const request = require('request-promise-native')
     const reqOpts = {
       method: 'GET',
       resolveWithFullResponse: true,

packages/@vue/cli-shared-utils/lib/validate.js

@@ -1,11 +1,10 @@
-const joi = require('joi')
 const { exit } = require('./exit')
 
 // proxy to joi for option validation
-exports.createSchema = fn => fn(joi)
+exports.createSchema = fn => fn(require('joi'))
 
 exports.validate = (obj, schema, cb) => {
-  joi.validate(obj, schema, {}, err => {
+  require('joi').validate(obj, schema, {}, err => {
     if (err) {
       cb(err.message)
       if (process.env.VUE_CLI_TEST) {
@@ -18,7 +17,7 @@ exports.validate = (obj, schema, cb) => {
 }
 
 exports.validateSync = (obj, schema) => {
-  const result = joi.validate(obj, schema)
+  const result = require('joi').validate(obj, schema)
   if (result.error) {
     throw result.error
   }

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

@@ -1,15 +1,13 @@
 const fs = require('fs')
 const ejs = require('ejs')
 const path = require('path')
-const globby = require('globby')
 const merge = require('deepmerge')
 const resolve = require('resolve')
 const isBinary = require('isbinaryfile')
-const yaml = require('yaml-front-matter')
 const mergeDeps = require('./util/mergeDeps')
 const stringifyJS = require('./util/stringifyJS')
-const { warn, getPluginLink, toShortPluginId } = require('@vue/cli-shared-utils')
 const ConfigTransform = require('./ConfigTransform')
+const { getPluginLink, toShortPluginId } = require('@vue/cli-shared-utils')
 
 const isString = val => typeof val === 'string'
 const isFunction = val => typeof val === 'function'
@@ -107,6 +105,7 @@ class GeneratorAPI {
       !options.file
     ) {
       if (hasReserved) {
+        const { warn } = require('@vue/cli-shared-utils')
         warn(`Reserved config transform '${key}'`)
       }
       return
@@ -167,6 +166,7 @@ class GeneratorAPI {
       source = path.resolve(baseDir, source)
       this._injectFileMiddleware(async (files) => {
         const data = this._resolveData(additionalData)
+        const globby = require('globby')
         const _files = await globby(['**/*'], { cwd: source })
         for (const rawPath of _files) {
           let filename = path.basename(rawPath)
@@ -311,6 +311,7 @@ function renderFile (name, data, ejsOptions) {
   //   - !!js/regexp /foo/
   //   - !!js/regexp /bar/
   // ---
+  const yaml = require('yaml-front-matter')
   const parsed = yaml.loadFront(template)
   const content = parsed.__content
   let finalTemplate = content.trim() + `\n`

packages/@vue/cli/lib/util/stringifyJS.js

@@ -1,6 +1,5 @@
-const stringify = require('javascript-stringify')
-
 module.exports = function stringifyJS (value) {
+  const stringify = require('javascript-stringify')
   return stringify(value, (val, indent, stringify) => {
     if (val && val.__expression) {
       return val.__expression