原生js封装数组API pop, push, reverse, sort，shift，unshift等，前端笔试题

1.  排序sort
     

   Array.prototype.sorts=function(){for(var i=0;i<arr.length;i++){var min = i;for(var j=i+1;j<arr.length;j++){if(arr[j]<arr[min]){min = j}}var temp = arr[i]arr[i] = arr[min]arr[min] = temp}  return arr;}

2.  反转reverse
       

  Array.prototype.newReverse= function(){for(i=0,j=this.length-1;j>i;j--,i++){var temp = this[i]this[i] = this[j]this[j] = temp}return this}var a = [1,2,3,4,5,6,7,8]a.newReverse()console.log(a)

3.  入栈push
     

  Array.prototype.myPush = function(item){this[this.length] = item;return this.length}var a = [1,2,3,4]a.myPush(5)console.log(a)

4.   出栈pop
     

  Array.prototype.myPop = function(){var b=this.length;var result = this[b-1];this.length = b - 1;return result;}var a = [1,2,3,4]console.log(a.myPop())console.log(a);

5.入队unshift

Array.prototype.myUnshift = function(item){this.length = this.length+1for(var i=this.length-1;i>=0;i--){this[i]=this[i-1]}this[0]=itemreturn this.length}var a = [1,2,3,4]a.myUnshift(100)console.log(a)

6.出队shift

       Array.prototype.myShift = function(){var result = this[0]for(var i=0;i<this.length-1;i++){this[i] = this[i+1]}this.length = this.length-1return result;}var a = [1,2,3,4]a.myShift()console.log(a)