新记录自动更新阵列中的旧记录

Question

嗨，我正在尝试将2行存储在数组中，但是第二行正在更新已存储的第一行。

  UserRole: UserRoleDTO;
  UserRoleArray: UserRoleDTO[];     
  rolesstring=["1","2"]      
  this.roleidArray = rolesstring.split(',');
  let UserArrayData = [];
  let count = 0;
  for (let roledata of this.roleidArray) {
    this.UserRole.roleid = +roledata;
    this.UserRole.userid = +UserId;
    this.UserRole.isactive = 1;
    this.UserRole.entryby = 1;
    console.log('RoleId which need to store in UserArrayData :' + this.UserRole.roleid);
    UserArrayData[count] = this.UserRole;
    console.log('Data stored in UserArrayData :' + UserArrayData[count].roleid);
    count = count + 1;
  }
  this.UserRoleArray = UserArrayData;
  console.log('RoleId which is stored in UserArrayData[0]:' + UserArrayData[0].roleid);// here it is always showing the last roleid stored

UserArrayData [0] .roleid的结果应为1，但显示为2。

Answer 1

这是深度克隆的问题，因为每当您分配UserArrayData[count] = this.UserRole;时，它都会分配其引用。因此，要解决此问题，您需要将深层副本分配给Object.assign。

尝试一下：

 UserArrayData[count] = Object.assign({}, this.UserRole);

或者按照@JB的建议，您可以在fol循环内创建局部变量。

尝试一下：

  for (let roledata of this.roleidArray) {
    let tmpObj = this.UserRole;
    tmpObj.roleid = +roledata;
    tmpObj.userid = +UserId;
    tmpObj.isactive = 1;
    tmpObj.entryby = 1;
    console.log('RoleId which need to store in UserArrayData :' + tmpObj.roleid);
    UserArrayData[count] = this.UserRole;
    console.log('Data stored in UserArrayData :' + UserArrayData[count].roleid);
    count = count + 1;
  }