js遍历效率

1w条数据，遍历效率

1、for

15s

    let t=(new Date()).getTime()let a=[]for(var i = 0; i < 100000; i++){a.push({id:i,val:i})}let ts=[]for(var i = 0; i < a.length; i++){if(a[i].val!=2 && a[i].val!=4 && a[i].val!=8){ts.push(a[i])}}let c=(new Date()).getTime()console.log(c-t,t,c,ts)//15

2、map

14s

    let t=(new Date()).getTime()let a=[]for(var i = 0; i < 100000; i++){a.push({id:i,val:i})}let ts=[]a.map(x=>{if(x.val!=2 && x.val!=4 && x.val!=8){ts.push(x)}})let c=(new Date()).getTime()console.log(c-t,t,c,ts)//14

3、forEach

19s

   let t=(new Date()).getTime()let a=[]for(var i = 0; i < 100000; i++){a.push({id:i,val:i})}let ts=[]a.forEach(x=>{if(x.val!=2 && x.val!=4 && x.val!=8){ts.push(x)}})let c=(new Date()).getTime()console.log(c-t,t,c,ts)//19

4、filter+forEach

21s

    let t=(new Date()).getTime()let a=[]for(var i = 0; i < 100000; i++){a.push({id:i,val:i})}let ts=[]a.filter(x=>x.val!=2 && x.val!=4 && x.val!=8).forEach(x=>{ts.push(x)})let c=(new Date()).getTime()console.log(c-t,t,c,ts) //21

5、filter+map

35s

    let t=(new Date()).getTime()let a=[]for(var i = 0; i < 100000; i++){a.push({id:i,val:i})}let ts=[]a.filter(x=>x.val!=2 && x.val!=4 && x.val!=8).map(x=>{ts.push(x)})let c=(new Date()).getTime()console.log(c-t,t,c,ts)  //35```