Class MatSortHeader

src/material/sort/sort-header.ts:62–236

  encapsulation: ViewEncapsulation.None,
})
export class MatSortHeader implements MatSortable, OnDestroy, OnInit, AfterViewInit {
  protected _sort = inject(MatSort, {optional: true})!;
  private _columnDef = inject(CdkColumnDef, {optional: true});
  private _changeDetectorRef = inject(ChangeDetectorRef);
  private _focusMonitor = inject(FocusMonitor);
  private _elementRef = inject<ElementRef<HTMLElement>>(ElementRef);
  private _ariaDescriber = inject(AriaDescriber, {optional: true});
  private _renderChanges: Subscription | undefined;
  protected _animationsDisabled = _animationsDisabled();

  /**
   * Indicates which state was just cleared from the sort header.
   * Will be reset on the next interaction. Used for coordinating animations.
   */
  protected _recentlyCleared = signal<SortDirection | null>(null);

  /**
   * The element with role="button" inside this component's view. We need this
   * in order to apply a description with AriaDescriber.
   */
  private _sortButton!: HTMLElement;

  /**
   * ID of this sort header. If used within the context of a CdkColumnDef, this will default to
   * the column's name.
   */
  @Input('mat-sort-header') id!: string;

  /** Sets the position of the arrow that displays when sorted. */
  @Input() arrowPosition: SortHeaderArrowPosition = 'after';

  /** Overrides the sort start value of the containing MatSort for this MatSortable. */
  @Input() start!: SortDirection;

  /** whether the sort header is disabled. */
  @Input({transform: booleanAttribute})
  disabled: boolean = false;

  /**
   * Description applied to MatSortHeader's button element with aria-describedby. This text should
   * describe the action that will occur when the user clicks the sort header.
   */
  @Input()
  get sortActionDescription(): string {
    return this._sortActionDescription;
  }
  set sortActionDescription(value: string) {
    this._updateSortActionDescription(value);
  }
  // Default the action description to "Sort" because it's better than nothing.
  // Without a description, the button's label comes from the sort header text content,
  // which doesn't give any indication that it performs a sorting operation.
  private _sortActionDescription: string = 'Sort';

  /** Overrides the disable clear value of the containing MatSort for this MatSortable. */
  @Input({transform: booleanAttribute})
  disableClear!: boolean;