JavaScript深拷贝与浅拷贝实现详解

        let arr = [1, 2, 3]
        let copyArr = [...arr]
        copyArr.push(4)
        console.log(arr, copyArr) 

        let arr2 = [[1, 2, 3], [9, 0, 6]]
        let copyArr2 = [...arr2]
        copyArr2[0].push(77)
        console.log(arr2, copyArr2)

const a1 = [1, 2];
const a1Copy = a1;
a1Copy[0] = 9;
console.log(a1)  // [9, 2]
console.log(a1Copy) // [9, 2]

const a1 = [1, 2];
const a1Copy = a1.concat();
a1Copy[0] = 9;
a1 // [1, 2]

const newObj = JSON.parse(JSON.stringify(oldObj))

function deepClone(source) {
    // 定义结果对象或数组
    const targetObj = source.constructor === Array ? [] : {}
    // 遍历key
    for (let keys in source) {
        // 如果key是对象的自有属性
        // hasOwnProperty()查找一个对象是否有某个属性，但是不会去查找它的原型链。
        if (source.hasOwnProperty(keys)) {
            // 如果是引用类型
            if (source[keys] && typeof source[keys] === 'object') {
                // 递归
                targetObj[keys] = deepClone(source[keys])
            } else {
                // 如果是基本类型
                targetObj[keys] = source[keys]
            }
        }
    }
    return targetObj
}

let obj = {
  a: [1, 2],
  b: "eee",
  c: 3,
};
let cloneObj = structuredClone(obj);
cloneObj.a[0] = 10;
console.log(cloneObj.a[0]); // 10
console.log(obj.a[0]);      // 1