如何在方法中取消订阅 function？

Question

使用 angular js 处理对话框组件，现在我发现我的 function 已订阅，并且在 if 条件下不退出方法，但继续执行另一个afterClosed()代码示例：

openCreateNewContentDialog(): void {
    const oldData = this.dataSource.data;
    const dialogConfig = AppConstants.matDialogConfig();
    const dialog = this.dialog.open(LicenseDialogComponent, dialogConfig);

    dialog.beforeClosed().subscribe(licenceDate => {
      for (const datesToCheck of oldData) {
        const newDateFrom = new Date(licenceDate.expirationDateFrom);
        const oldDateTo = new Date(datesToCheck.expirationDateTo.toString());
        if (newDateFrom <= oldDateTo) {
          // console.log('return?');
          return;
        }
      }
    });

    dialog.afterClosed().subscribe(licence => {
      if (licence) {
        this._value.push(licence);
        this.dataSource.data = this.value;
        this.change();
      }
    });
  }

取消订阅beforeClosed() function 的最佳和优化方法是什么？

Answer 1

因此，根据您的描述，我知道t want a second subscription to happen if the condition in the first subscriber is true, right? But you subscription will happen anyway because you instantiated it in the method, the code in the subscribe() it's just a callback. So if you don t want a second subscription to happen if the condition in the first subscriber is true, right? But you subscription will happen anyway because you instantiated it in the method, the code in the subscribe() it's just a callback. So if you don t want a second subscription to happen if the condition in the first subscriber is true, right? But you subscription will happen anyway because you instantiated it in the method, the code in the subscribe() it's just a callback. So if you don不想进行大量重写，我建议将订阅存储在变量中，这样您就可以访问它们并且可以随时取消订阅。

openCreateNewContentDialog(): void {
const oldData = this.dataSource.data;
const dialogConfig = AppConstants.matDialogConfig();
const dialog = this.dialog.open(LicenseDialogComponent, dialogConfig);

const beforeClosed = dialog.beforeClosed().subscribe(licenceDate => {
  for (const datesToCheck of oldData) {
    const newDateFrom = new Date(licenceDate.expirationDateFrom);
    const oldDateTo = new Date(datesToCheck.expirationDateTo.toString());
    if (newDateFrom <= oldDateTo) {
      // console.log('return?');
      afterClosed.unsubscribe();
      return;
    }
  }
});

const afterClosed = dialog.afterClosed().subscribe(licence => {
  if (licence) {
    this._value.push(licence);
    this.dataSource.data = this.value;
    this.change();
  }
});

}

我希望它有帮助！ 如果您必须处理多个订阅，您也可以尝试https://www.digitalocean.com/community/tutorials/angular-takeuntil-rxjs-unsubscribe 。