js 删除对象的属性

方法1

let obj ={
    a:1,
    b:2,
    c:3
}
delete obj.a
delete obj['a']

• 彻底删除key value
• 速度较慢

方法2

let obj ={
    a:1,
    b:2,
    c:3
}
obj.a =undefine

• 速度快
• key还在

https://flaviocopes.com/how-to-remove-object-property-javascript/