SOURCE

class User {
    username = new Map();
    password: any;
}
function test(){
    console.log("onload")
    const mode = "phone";
    let userInfo = new User();
    let userMap = new Map();
    console.log(typeof userInfo.username);
    userInfo.username.set(mode,"1812233789");
    console.log(userInfo.username.get(mode));
    console.log(userInfo)
    console.log({[mode]:111});
    console.log(new Map()
}
test();