/*数组中，取出满足要求的第一个值*/
    const myArr=[1,2,3,4,8,12];
    var v1=myArr.find(value=>value>8);
    console.log(v1);
 
    /*通过数组下标取对应值*/
    var v2=myArr.find((value,index,arr)=>{
        return index==4
    });
    console.log(v2);
 
    /*对象，取出满足要求的下标*/
    const nameArr=[
        {id:1,userName:"zhaoqian",age:27},
        {id:2,userName:"sunli",age:23},
        {id:3,userName:"zhouwu",age:25 },
        {id:4,userName:"zhengwang",age:21}];
    /*满足条件，返回下标位置2*/
    var i1=nameArr.findIndex((value)=>value.age==25);
    console.log(i1);
    /*没有满足条件的，返回-1*/
    var i2=nameArr.findIndex((value)=>value.age==28);
    console.log(i2);