JS 复制数组和对象

复制数组

• 错误

let a = [1,2,3];
let b = a; //a受影响
b.push(4);
console.log(a); //[1, 2, 3, 4]
console.log(b); //[1, 2, 3, 4]

• 正确复制数组

let c = [...a]; //复制

let c = JSON.parse(JSON.stringify(a)); //复制

let c = a.concat([]); //复制

复制对象

let newObj;
Object.keys(oldObj).forEach(k => (newObj[`${k}`] = res[k]));