Js给空数组生成1-n的值

方法一：循环赋值

var arr = new Array(100);
for(var i=0;i<arr1.length;i++){
arr1[i] = i;
}

方法二：push方法实现

var arr = new Array();
for(var i=0;i<100;i++){
 arr.push(i);
}

方法三：while

var arr = new Array();
var i = 0;
while(i<100){
arr.push(i);
i++;
}

方法四：do while

var arr = new Array();
var i = 0;
do{
arr.push(i);
i++;
}
while(i<100)

方法五：Object.keys

var arr = Object.keys(Array.apply(null, {length:100})).map(function(item){
return +item;
});

方法六：Array.from

var arr = Array.from({length:100}, (v,k) => k);

方法七：Array.from

var arr = Array.from(Array(100), (v,k) =>k);

方法八：new Array

var arr = new Array(100).keys();

方法九：setInterval

var arr = [];
var i = 0;
var timer = setInterval(function(){
 arr[i] = ++i;
 if(i>=100){
  clearInterval(timer);
 }
},1);

方法十：递归

var arr = [];
var i = 0;
function MakeArray(num){
if(i<num){
arr[i] = i++;
 MakeArray(num);
 }
 return arr;
}

方法十一：map

var arr = new Array(100).toString().split(',').map(function(item,index){
 return index;
});