js 一些数组方法

findIndex --裁剪

let index = this.options.findIndex(item=> item.value == val)
this.comList.push(this.options[index])
this.options.splice(index, 1);

findIndex 返回数组下标

filter--过滤

var newList = [...this.list] //...深拷贝，JSON.parse(JSON.Stringify),split 
newList = newList.filter(item=>item.id !== id) //删除过滤

filter不改变原数组，所以要重新赋值

indexOf,includes--可判断数组，也可以判断字符串，判断有无，下标

let languages = ["JavaScript",  "C", "Java","C++", "Python", "Lua"];
let check = languages.includes("Java"); //有java返回true，没有返回false
languages.indexOf("Java") //有就返回下标2，没有返回-1