CommonJs模块和 ES6模块的差异

CommonJS模块 输出值的拷贝，ES6模块 输出 值的引用

// a.js
let user = 'xxx'
const setUser = (val) => {
    user = val
}
module.exports = { user, setUser}

// b.js
const { user, setUser } = require('./a.js')
console.log(user) // xxx
setUser('yyy') 
console.log(user) // xxx

当前的 user 并没有改变

CommonJs的拷贝为浅拷贝

// a.js

let user = {
    name: '?',
    abilitys: {
        say() { 
            console.log('hi')
        },
        play: 'js'
    }
}
const changeAbility = (val) => {
    user.abilitys = {...user.abilitys, ...val}
}
module.exports = { user, changeAbility}

// b.js
const { user, changeAbility } = require('./a.js')
console.log(user.abilitys.play) // js
changeAbility({ play: 'css' }) 
console.log(user.abilitys.play) // css

user.abilitys.play 更改为了 css

• CommonJS模块 运行时加载，ES6模块 编译时输出接口
• CommonJS模块 同步加载模块，ES6模块 异步加载