babel踩坑

1.安装babel-cli babel-preset-env

首先通过npm init -y命令生成package.json
然后命令行输入

npm install --save-dev babel-cli babel-preset-env

2.配置.babelrc文件

2.1.presets预设配置

{
    "presets": [
        "env"
    ]
}

2.2plugin插件配置

暂时不表

也可以通过package.json指定babel文件位置

{
  "name": "my-package",
  "version": "1.0.0",
  "babel": {
    // my babel config here
  }
}

3增加scripts命令，进行编译

{
  "name": "babel-test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "babel src -d dist"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-cli": "^6.26.0",
    "babel-preset-env": "^1.7.0"
  }
}

然后只需要 npm run build就ok啦
所有src的js文件都会编译到dist中
比如

let a = res => {
    return `ds${res}fsfd`
}

就会被编译成

"use strict";

var a = function a(res) {
    return "ds" + res + "fsfd";
};