js中的数组删除、对象属性删除

删除数组中的元素

使用splice(会改变原数组)

  arr.splice(index,len,item);
   //index,删除或者替换的起始位置
   //len,删除或者替换的长度
   //item,替换的内容
   arr = ["a","b","c","d"]
   //删除
   arr.splice(1,2) ====>["a","d"]
   //替换
   arr.splice(1,1,"tt") ====> ["a","tt","c","d"]
   arr.splice(1,2,"tt") ====> ["a","tt","d"]
   //添加
   arr.splice(1,0,"ttt") ====> ["a","tt","b","c","d"]

使用remove删除指令的元素

arr.remove(xx)

使用delete

//数组长度不变，置为undefined
    delete arr[1] ====> ["a",,"c","d"]

删除对象的属性

使用delete

delete obj.properti
let map = new Map(["name","xxx"])
map.delete("name")