# vue-cli/bin/vue-init
// ...
var template = program.args[0]
var hasSlash = template.indexOf('/') > -1
var rawName = program.args[1]
// ...

# vue-cli/bin/vue-init
// ...
var tmp = path.join(home, '.vue-templates', template.replace(/\//g, '-'))
if (program.offline) {
  console.log(`> Use cached template at ${chalk.yellow(tildify(tmp))}`)
  template = tmp
}
// ...

# vue-cli/lib/generate.js

//...

// register handlebars helper
Handlebars.registerHelper('if_eq', function (a, b, opts) {
  return a === b
    ? opts.fn(this)
    : opts.inverse(this)
})

Handlebars.registerHelper('unless_eq', function (a, b, opts) {
  return a === b
    ? opts.inverse(this)
    : opts.fn(this)
})

# vue-cli/lib/options.js
// ...
// dir 是模板下载成功之后的临时路径
var json = path.join(dir, 'meta.json')
var js = path.join(dir, 'meta.js')
var opts = {}

// ...

# vue-cli/lib/generate.js
// ...
// src 是模板下载成功之后的临时路径
var opts = getOptions(name, src)  
var metalsmith = Metalsmith(path.join(src, 'template'))

// ...

//vue-cli/lib/generate.js#L53-L55

metalsmith.use(askQuestions(opts.prompts))
	.use(filterFiles(opts.filters))
	.use(renderTemplateFiles(opts.skipInterpolation))

function askQuestions (prompts) {
  return function (files, metalsmith, done) {
    ask(prompts, metalsmith.metadata(), done)
  }
}

// meta.{js,json}
{
    "prompts": {
    	"name": {
        	"type": "string",
        	"required": true,
	       "message" : "Project name"
	    },
	    "version": {
	       "type": "input",
	       "message": "project's version",
	       "default": "1.0.0"
	    }
    }
}

// vue-cli/lib/ask.js#prompt

inquirer.prompt([{
	type: prompt.type,
	message: prompt.message,
	default: prompt.default
	//...
}], function(answers) {
	// 保存用户的输入
})

// global metadata
{
	name: 'test',
	version: '0.1.1'
	// ...
}

function filterFiles (filters) {
  return function (files, metalsmith, done) {
    filter(files, filters, metalsmith.metadata(), done)
  }
}

module.exports = function (files, filters, data, done) {
  // 没有 filters 直接返回
  if (!filters) {
    return done()
  }
  
  // 获取所有的文件名(即路径, eg: test/**)
  var fileNames = Object.keys(files)
 	
  // 遍历 filters
  Object.keys(filters).forEach(function (glob) {
    fileNames.forEach(function (file) {
      if (match(file, glob, { dot: true })) {
        // 获取到匹配的值
        var condition = filters[glob]
        if (!evaluate(condition, data)) {
          // 删除文件
          delete files[file]
        }
      }
    })
  })
  done()
}

// vue-cli/lib/eval.js

var fn = new Function('data', 'with (data) { return ' + exp + '}')

// vue-cli/lib/generate.js#renderTemplateFiles

// ...
var render = require('consolidate').handlebars.render
var async = require('async')
// ...

function renderTemplateFiles(//...){
	return function (files, metalsmith, done) {
		var keys = Object.keys(files)
    	var metalsmithMetadata = metalsmith.metadata()
    	
    	// 遍历 keys
    	async.each(keys, function(file, next){
    		// 读取文件内容
    		var str = files[file].contents.toString()
    		
    		// 不渲染不含mustaches表达式的文件
    		if (!/{{([^{}]+)}}/g.test(str)) {
	        	return next()
	      	}
	      	
	      	// 调用 handlebars 渲染文件
	      	render(/* 渲染文件 */)
    	     })
	}
}

// vue-cli/lib/generate.js

// ...
var opts = getOptions(name, src)

// ...

if (typeof opts.complete === 'function') {
	var helpers = {chalk, logger, files}
	opts.complete(data, helpers)
} else {
	logMessage(opts.completeMessage, data)
}

// ...

// ...
var request = require('request')

//...

request({
	url: 'https://api.github.com/users/vuejs-templates/repos',
   headers: {
     'User-Agent': 'vue-cli'
   }
}, function(err, res, body) {
	// 在终端输出列表
})

// meta.{js,json}
{
    "prompts": {
    	"name": {
        	"type": "string",
        	"required": true,
	       "message" : "Project name"
	    },
	    "test": {
        	"type": "confirm",
	       "message" : "Unit test?"
	    },
	    "version": {
	       "type": "input",
	       "message": "project's version",
	       "default": "1.0.0"
	    }
    }
}

// template/package.json

{{#test}}
"test": "npm run test"
{{/test}}

// ...

if (prompt.when && !evaluate(prompt.when, data)) {
	return done()
}

//...

{
  "prompts": {
    "lint": {
        "type": "confirm",
        "message": ""Use ESLint to lint your code?"
    },
    "eslint": {
      "when": "lint",
      "type": "list",
      "message": "Pick a lint config",
      "choices": [
        "standard",
        "airbnb",
        "none"
      ]
    }
  }
}

{
  "prompts": {
      "unit": {
          "type": "confirm",
          "message": "Setup unit tests with Mocha?"
      }
  },  
  "filters": {
    "test/*": "unit"
  }
}

{
	"helpers": {
	    "if_or": function (v1, v2, options) {
	      if (v1 || v2) {
	        return options.fn(this);
	      }
	
	      return options.inverse(this);
	    }
  	},
}

{{#if_or val1 val2}}
// 当 val1 或者 val2 为 true 时, 这里才会被渲染
{{/if_or}}

{
	"complete": function(data, helpers) {}
}

// vue-cli/lib/generate.js

// ...
var data = Object.assign(metalsmith.metadata(), {
	destDirName: name,
	inPlace: dest === process.cwd(),
	noEscape: true
})

// ...

// files 是 metalsmith build 之后的文件对象
var helpers = {chalk, logger, files}

// ...