Object.assign解析

let params = Object.assign({username:this.username},values)

assign是将括号中所有参数合并，并赋值给params，如下图所示

values={"oldpassword":"COMAC.123","password":"123456","confirmpassword":"123456"}

params={username: "admin", oldpassword: "COMAC.123", password: "123456", confirmpassword: "123456"}