javascript浅拷贝与深拷贝

浅拷贝

1. Object.assign()

const originArray = [1,2,3,4,5,[6,7,8]];
const cloneArray = Object.assign({}, orignArray);

2. 首层浅拷贝

function shallowClone(source) {
  const targetObj = source.constructor === Array ? [] : {}; // 判断复制的目标是数组还是对象
  for (let keys in source) { // 遍历目标
    if (source.hasOwnProperty(keys)) {
      targetObj[keys] = source[keys];
    }
  }
  return targetObj;
}

3. concat

const originArray = [1,2,3,4,5,[6,7,8]];
const cloneArray = originArray.concat();

4. slice

const originArray = [1,2,3,4,5,[6,7,8]];
const cloneArray = originArray.slice();

5. …扩展运算符

const originArray = [1,2,3,4,5,[6,7,8]];
const originObj = {a:1,b:{bb:1}};

const cloneArray = [...originArray];

const cloneObj = {...originObj};

深拷贝

1. JSON.parse()和JSON.stringfy()

2. 递归

function deepClone(obj) {
	if (obj === null || typeof obj !== 'object') {
		return obj;
	}
	let result = Array.isArray(obj) ? [] : {};
	for (let key in obj) {
		if (obj.hasOwnProperty(key)) {
			result[key] = deepClone(obj[key]);
		}
	}
	return result;
}

  //使用递归实现深拷贝
     function deepClone(obj) {
         //判断拷贝的obj是对象还是数组
         var objClone = Array.isArray(obj) ? [] : {};
         if (obj && typeof obj === "object") { //obj不能为空，并且是对象或者是数组 因为null也是object
             for (key in obj) {
                 if (obj.hasOwnProperty(key)) {
                     if (obj[key] && typeof obj[key] === "object") { //obj里面属性值不为空并且还是对象，进行深度拷贝
                         objClone[key] = deepClone(obj[key]); //递归进行深度的拷贝
                     } else {
                         objClone[key] = obj[key]; //直接拷贝
                     }
                 }
             }
         }
         return objClone;
     }