ES5 深拷贝&浅拷贝

浅拷贝

遍历赋值

 
const student = {
    name: 'anjiyu',
    sex: 'female',
    studyInfo: {
        school: '河南大学',
        level: '本科',
        posi: '学士'
    }
}
function deepCopy(srcObj){
    const resObj = {};
    if(srcObj instanceof Array){
        resObj = [];
    }
    for(const key in srcObj){
        resObj[key] = srcObj[key];
    }
    return resObj;
}

const newStu = deepCopy(student);
newStu.studyInfo.school = '河大';
console.log(`老同学的信息`,student);
/*
老同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河大', level: '本科', posi: '学士' }
}
 */
console.log(`新同学的信息`,newStu);
/*
新同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河大', level: '本科', posi: '学士' }
}
*/

Object.create()

以传入对象作为原型创建一个新对象，并返回。

 
const student = {
    name: 'anjiyu',
    sex: 'female',
    studyInfo: {
        school: '河南大学',
        level: '本科',
        posi: '学士'
    }
}

const newStu = Object.create(student);
newStu.studyInfo.school = '河大';
console.log(`老同学的信息`,student);
/*
老同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河大', level: '本科', posi: '学士' }
}
 */
console.log(`新同学的信息`,newStu.__proto__);
/*
新同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河大', level: '本科', posi: '学士' }
}
*/

深拷贝

递归赋值

 
const student = {
    name: 'anjiyu',
    sex: 'female',
    studyInfo: {
        school: '河南大学',
        level: '本科',
        posi: '学士'
    }
}
function deepCopy(srcObj){
    const resObj = {};
    if(srcObj instanceof Array){
        resObj = [];
    }
    for(const key in srcObj){
        const value = srcObj[key];
        if(typeof value === 'object'){
            resObj[key] = deepCopy(value);
        }else{
            resObj[key] = value;
        }
    }
    return resObj;
}

const newStu = deepCopy(student);
newStu.studyInfo.school = '河大';
console.log(`老同学的信息`,student);
/*
老同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河南大学', level: '本科', posi: '学士' }
}
 */
console.log(`新同学的信息`,newStu);
/*
新同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河大', level: '本科', posi: '学士' }
}
*/

JSON.parse JSON.stringify

这种方法比较常用

 
const student = {
    name: 'anjiyu',
    sex: 'female',
    studyInfo: {
        school: '河南大学',
        level: '本科',
        posi: '学士'
    }
}

const newStu = JSON.parse(JSON.stringify(student));
newStu.studyInfo.school = '河大';
console.log(`老同学的信息`,student);
/*
老同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河南大学', level: '本科', posi: '学士' }
}
 */
console.log(`新同学的信息`,newStu.__proto__);
/*
新同学的信息 {
  name: 'anjiyu',
  sex: 'female',
  studyInfo: { school: '河大', level: '本科', posi: '学士' }
}
*/