猫眼二面

1. let a = Foo();
   console.log(a instanceof Foo) // true
   console.log(a.val); // 1
   let b = Foo();
   console.log(b.val); // 2
   let c = Foo();
   console.log(c.val); // 3

var index = 0
class Foos{
constructor(){
this.val = ++index;
//Number(this.ins(index))
}
ins(index){
return index++
}
}
function Foo(){
return new Foos()
}

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

Array.prototype.multiply = function(){
// let arrCopy = this;
let newArr = this.map((x)=>{
return x*x;
})
return this.concat(newArr.reverse())
}

function foo(a, b, c){
return a+b+c;
}

3. foo(1,2,3) // 6

curry(foo)(1)(2)(3) // 6

function curry(args){
if(!typeof args === ‘Number’){
return args()
}else{
}
}

4. 200 from cache

5. let a = [12, 21, 34, 153];let b = [10, 33, 52];
   我可真菜啊~~~