Method _resetOptions

src/material/select/select.ts:1199–1222

Drops current option subscriptions and IDs and resets from scratch.

()

  /** Drops current option subscriptions and IDs and resets from scratch. */
  private _resetOptions(): void {
    const changedOrDestroyed = merge(this.options.changes, this._destroy);

    this.optionSelectionChanges.pipe(takeUntil(changedOrDestroyed)).subscribe(event => {
      this._onSelect(event.source, event.isUserInput);

      if (event.isUserInput && !this.multiple && this._panelOpen) {
        this.close();
        this.focus();
      }
    });

    // Listen to changes in the internal state of the options and react accordingly.
    // Handles cases like the labels of the selected options changing.
    merge(...this.options.map(option => option._stateChanges))
      .pipe(takeUntil(changedOrDestroyed))
      .subscribe(() => {
        // `_stateChanges` can fire as a result of a change in the label's DOM value which may
        // be the result of an expression changing. We have to use `detectChanges` in order
        // to avoid "changed after checked" errors (see #14793).
        this._changeDetectorRef.detectChanges();
        this.stateChanges.next();
      });
  }

  /** Invoked when an option is clicked. */
  private _onSelect(option: MatOption, isUserInput: boolean): void {