[面经]-[快手]-[电商]-[2020.03.30]

[L1116]

1.文字的颜色

<style>
	.classA{
        color:blue;
	}
	.classB{
        color:red;
	}
</style>
<p class="classB classA">123</p>

2.child的border，padding，盒子大小

<style>
    .parent {
      background: red;
      width: 100px;
      height: 100px;
      padding: 0;
      margin: 0;
    }

    .child {
      background: green;
      width: 50px;
      height: 50px;
      padding: 10%;
      border: 10px solid black;
      box-sizing: border-box;
    }
</style>
<div class="parent">
   <div class="child"></div>
</div>

3. 代码的执行结果

Function.prototype.a = () => alert(1);
Object.prototype.b = () => alert(2);
function A() {}
const a = new A();
a.a();
a.b();
a.__proto__ = ?
A.prototype = ?

var x = 10;
function a(y) {
  var x = 20;
  return b(y);
}

function b(y) {
  return x + y
}

a(20);

console.log(1);

setTimeout(() => {
  console.log(2)
});

process.nextTick(() => {
  console.log(3);
});

setImmediate(() => {
  console.log(4)
});

new Promise(resolve => {
  console.log(5);
  resolve();
  console.log(6);
}).then(() => {
  console.log(7)
});

Promise.resolve().then(() => {
  console.log(8);
  process.nextTick(() => {
    console.log(9)
  });
});

6.数组随机洗牌，请实现一个算法，实现数组乱序，要求每个数字出现在每个位置的概率是平均的

function radomArr(arr){
   
    return arr.sort(compare)
}

function compare(){
         var x = Math.random()
        //console.log(x)
         var label = x > 0.5 ? 1 : -1
         return label
}


console.log(radomArr([1,2,3,4,5]))

7. 实现add，one，two三个方法

function add() {
}

function one() {
}

function two() {
}

console.log(one(add(two())))
// 3
console.log(two(add(one())))
// 3

8 数字逆转，不可以使用数组或者字符串的reverse方法
123 -> 321
-56 -> -65
780 -> 87