Function ɵɵprojectionDef

packages/core/src/render3/instructions/projection.ts:96–131

(projectionSlots?: (string | (string | number)[][])[])

 * @codeGenApi
 */
export function ɵɵprojectionDef(projectionSlots?: (string | (string | number)[][])[]): void {
  const componentNode = getLView()[DECLARATION_COMPONENT_VIEW][T_HOST] as TElementNode;

  if (!componentNode.projection) {
    // If no explicit projection slots are defined, fall back to a single
    // projection slot with the wildcard selector.
    const numProjectionSlots = projectionSlots ? projectionSlots.length : 1;
    const projectionHeads: (TNode | null)[] = (componentNode.projection = newArray(
      numProjectionSlots,
      null! as TNode,
    ));
    const tails: (TNode | null)[] = projectionHeads.slice();

    let componentChild: TNode | null = componentNode.child;

    while (componentChild !== null) {
      // Do not project let declarations so they don't occupy a slot.
      if (componentChild.type !== TNodeType.LetDeclaration) {
        const slotIndex = projectionSlots
          ? matchingProjectionSlotIndex(componentChild, projectionSlots as ProjectionSlots)
          : 0;

        if (slotIndex !== null) {
          if (tails[slotIndex]) {
            tails[slotIndex]!.projectionNext = componentChild;
          } else {
            projectionHeads[slotIndex] = componentChild;
          }
          tails[slotIndex] = componentChild;
        }
      }

      componentChild = componentChild.next;
    }
  }
}

/**
 * Inserts previously re-distributed projected nodes. This instruction must be preceded by a call