实现

面试题 实现

const a = [1, 2, 3, 4, 5];
// Implement this
a.multiply();
console.log(a); // [1, 2, 3, 4, 5, 1, 4, 9, 16, 25]

要求的是对a修改

const a = [1, 2, 3, 4, 5];
// Implement this
Array.prototype.multiply = function() {
    this.forEach(x => this.push(x * x))
}

a.multiply();
console.log(a); // [1, 2, 3, 4, 5, 1, 4, 9, 16, 25]

这种就不是对a修改了，而是返回一个值

const a = [1, 2, 3, 4, 5];
// Implement this
Array.prototype.multiply = function() {
    b=this.map((x)=>{
    ​  return x*x
    })
    c=[...this, ...b]
    return c
}

console.log(a.multiply()); // [1, 2, 3, 4, 5, 1, 4, 9, 16, 25]