JSON 拷貝

let result = JSON.parse(JSON.stringify(obj)) 深拷貝

Object.assign()
可枚舉的數(shù)據(jù)

 const obj = {}
      const obj1 = { name: 'tom' }
      const obj2 = { age: 34 }
      const obj3 = Object.assign(obj, obj1, obj2)
      console.log(obj3)
{name: 'tom', age: 34}
age: 34
name: "tom"

手寫深拷貝

        function deepClone (obj) {
            let newObj
            if (obj && typeof(obj) !== 'object') {
                newObj = obj
            } else if (obj && typeof(obj)  === 'object') {
                newObj = Array.isArray(obj) ? []: {}
                for(let key in obj) {
                    if (obj.hasOwnProperty(key)) {
                        if (obj[key] && typeof(obj[key]) === 'object') {
                            newObj[key] = deepClone(obj[key])
                        } else {
                            newObj[key] = obj[key]
                        }
                    }
                }
            }
    
            return newObj

        }


let test = {
    x : 1,
    y : 2,
    z : {
        a : 4,
        b : 5
    }
}
        
const result = deepClone(test)
test.x = 5
console.log(test,result)


{x: 5, y: 2, z: {…}} {x: 1, y: 2, z: {…}}