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@virtual

Tag type: modifier

TSDoc standardization: extended

The @virtual modifier has similar semantics to the virtual keyword in C#. It should only be applied to a member of a class. It indicates that the member may be overridden (i.e. redefined) by a corresponding member of a child class. The @virtual modifier should not be applied to abstract members, because the abstract keyword already implies that the method is virtual.

The @virtual modifier will be displayed in the generated documentation.

API Extractor does not currently validate whether the @virtual modifier is used correctly. (This may be implemented in the future.)

NOTE: Unlike many other programming languages, TypeScript supports inheritance for static members of a class. Thus, it is valid to use @virtual, @override, and @sealed for static members as well as instance members.

Usage example:

/** @public */
export class Control {
  /**
   * The title of the control
   * @virtual
   */
  public get title(): string {
    return 'Control';
  }

  /**
   * Draws the control on the screen
   * @virtual
   */
  public render(): void {
    . . .
  }
}

/** @public */
export class Button extends Control {
  /**
   * {@inheritDoc Control.title}
   * @override
   */
  public get title(): string {
    return 'Button';
  }

  /**
   * {@inheritDoc Control.render}
   * @override
   */
  public render(): void {
    . . .
  }
}

See also​