Class AttributePart

packages/lit-html/src/lit-html.ts:1801–1960

export type {AttributePart};
class AttributePart implements Disconnectable {
  readonly type:
    | typeof ATTRIBUTE_PART
    | typeof PROPERTY_PART
    | typeof BOOLEAN_ATTRIBUTE_PART
    | typeof EVENT_PART = ATTRIBUTE_PART;
  readonly element: HTMLElement;
  readonly name: string;
  readonly options: RenderOptions | undefined;

  /**
   * If this attribute part represents an interpolation, this contains the
   * static strings of the interpolation. For single-value, complete bindings,
   * this is undefined.
   */
  readonly strings?: ReadonlyArray<string>;
  /** @internal */
  _$committedValue: unknown | Array<unknown> = nothing;
  /** @internal */
  __directives?: Array<Directive | undefined>;
  /** @internal */
  _$parent: Disconnectable;
  /** @internal */
  _$disconnectableChildren?: Set<Disconnectable> = undefined;

  protected _sanitizer: ValueSanitizer | undefined;

  get tagName() {
    return this.element.tagName;
  }

  // See comment in Disconnectable interface for why this is a getter
  get _$isConnected() {
    return this._$parent._$isConnected;
  }

  constructor(
    element: HTMLElement,
    name: string,
    strings: ReadonlyArray<string>,
    parent: Disconnectable,
    options: RenderOptions | undefined
  ) {
    this.element = element;
    this.name = name;
    this._$parent = parent;
    this.options = options;
    if (strings.length > 2 || strings[0] !== '' || strings[1] !== '') {
      this._$committedValue = new Array(strings.length - 1).fill(new String());
      this.strings = strings;
    } else {
      this._$committedValue = nothing;
    }
    if (ENABLE_EXTRA_SECURITY_HOOKS) {
      this._sanitizer = undefined;
    }
  }