Function ɵɵrepeaterCreate

packages/core/src/render3/instructions/control_flow.ts:290–355

(
  index: number,
  templateFn: ComponentTemplate<unknown>,
  decls: number,
  vars: number,
  tagName: string | null,
  attrsIndex: number | null,
  trackByFn: TrackByFunction<unknown>,
  trackByUsesComponentInstance?: boolean,
  emptyTemplateFn?: ComponentTemplate<unknown>,
  emptyDecls?: number,
  emptyVars?: number,
  emptyTagName?: string | null,
  emptyAttrsIndex?: number | null,
)

 * @codeGenApi
 */
export function ɵɵrepeaterCreate(
  index: number,
  templateFn: ComponentTemplate<unknown>,
  decls: number,
  vars: number,
  tagName: string | null,
  attrsIndex: number | null,
  trackByFn: TrackByFunction<unknown>,
  trackByUsesComponentInstance?: boolean,
  emptyTemplateFn?: ComponentTemplate<unknown>,
  emptyDecls?: number,
  emptyVars?: number,
  emptyTagName?: string | null,
  emptyAttrsIndex?: number | null,
): void {
  performanceMarkFeature('NgControlFlow');

  ngDevMode &&
    assertFunction(
      trackByFn,
      `A track expression must be a function, was ${typeof trackByFn} instead.`,
    );

  const lView = getLView();
  const tView = getTView();
  const hasEmptyBlock = emptyTemplateFn !== undefined;
  const hostLView = getLView();
  const boundTrackBy = trackByUsesComponentInstance
    ? // We only want to bind when necessary, because it produces a
      // new function. For pure functions it's not necessary.
      trackByFn.bind(hostLView[DECLARATION_COMPONENT_VIEW][CONTEXT])
    : trackByFn;
  const metadata = new RepeaterMetadata(hasEmptyBlock, boundTrackBy);
  hostLView[HEADER_OFFSET + index] = metadata;

  declareNoDirectiveHostTemplate(
    lView,
    tView,
    index + 1,
    templateFn,
    decls,
    vars,
    tagName,
    getConstant(tView.consts, attrsIndex),
    TNodeFlags.isControlFlowStart,
  );

  if (hasEmptyBlock) {
    ngDevMode &&
      assertDefined(emptyDecls, 'Missing number of declarations for the empty repeater block.');
    ngDevMode &&
      assertDefined(emptyVars, 'Missing number of bindings for the empty repeater block.');

    declareNoDirectiveHostTemplate(
      lView,
      tView,
      index + 2,
      emptyTemplateFn,