1、Symbol,一个每次创建都不一样的值
Symbol undefined null Boolean String Number Object
let c=Symbol("这是一个Symbol"); let a=Symbol(); let b=Symbol(); console.log("a:",a); console.log("b:",b); console.log("c:",c);console.log(a===b);
let name=Symbol(); { var person={}; person[name]="file1"; } { person["name"]="file2"; } console.log("person:",person);
2、防止重写上游的值
let name=Symbol(); { var person={}; person[name]="file1"; console.log("person[name]:",person[name]); } { let name=Symbol(); person[name]="file2"; console.log("person[name]:",person[name]); console.log("person[name]:",person[name]); } console.log("person[name]:",person[name]);
时间: 2024-08-08 13:52:15