浅拷贝 深拷贝

let a = {
    age: 1
}
let b = a
a.age = 2
console.log(b.age) // 2

let a = {

  age: 1

}

let b = Object.assign({}, a)

a.age = 2

console.log(b.age) // 1

let a = {
  age: 1
}
let b = { ...a }
a.age = 2
console.log(b.age) // 1

let a = {
    age: 1,
    jobs: {
        first: 'FE'
    }
}
let b = { ...a }
a.jobs.first = 'native'
console.log(b.jobs.first) // native

let a = {
    age: 1,
    jobs: {
        first: 'FE'
    }
}
let b = JSON.parse(JSON.stringify(a))
a.jobs.first = 'native'
console.log(b.jobs.first) // FE

let obj = {
    a: 1,
    b: {
        c: 2,
        d: 3,
    },
}
obj.c = obj.b
obj.e = obj.a
obj.b.c = obj.c
obj.b.d = obj.b
obj.b.e = obj.b.c
let newObj = JSON.parse(JSON.stringify(obj))
console.log(newObj)

let a = {
    age: undefined,
    sex: Symbol('male'),
    jobs: function() {},
    name: 'yck'
}
let b = JSON.parse(JSON.stringify(a))
console.log(b) // {name: "yck"}

MessageChannel 简介

www.jianshu.com/p/4f07ef18b…

然后

function deepClone(obj) {
    function isObject(o) {
        return (typeof o === 'object' || typeof o === 'function') && o !== null
    }
    if (!isObject(obj)) {
        throw new Error('非对象')
    }
    let isArray = Array.isArray(obj)
    let newObj = isArray ? [...obj] : {...obj }
    Reflect.ownKeys(newObj).forEach(key=> {
        newObj[key] = isObject(obj[key]) ?deepClone(obj[key]) : obj[key]
    })
    return newObj
}
let obj = {
    a: [1, 2, 3],
    b: {
        c: 2,
        d: 3
    }
}
let newObj = deepClone(obj)
newObj.b.c = 1
console.log(obj.b.c) // 2