fixup! refactor(core): abstract control flow discovery utilities

Author: hawkgs

packages/core/src/render3/instructions/control_flow.ts

@@ -253,7 +253,7 @@ export function ɵɵrepeaterTrackByIdentity<T>(_: number, value: T) {
   return value;
 }
 
-class RepeaterMetadata {
+export class RepeaterMetadata {
   constructor(
     public hasEmptyBlock: boolean,
     public trackByFn: TrackByFunction<unknown>,

packages/core/src/render3/util/control_flow.ts

@@ -41,25 +41,22 @@ import {
   ControlFlowBlockType,
   DeferBlockData,
   ForLoopBlockData,
-  RepeaterMetadataShape,
 } from './control_flow_types';
 import {TNode} from '../interfaces/node';
+import {RepeaterMetadata} from '../instructions/control_flow';
 
 /**
  * Gets all of the control flow blocks that are present inside the specified DOM node.
  * @param node Node in which to look for control flow blocks.
- *
- * @publicApi
  */
 export function getControlFlowBlocks(node: Node): ControlFlowBlock[] {
-  const results: ControlFlowBlock[] = [];
   const lView = getLContext(node)?.lView;
 
   if (lView) {
-    findControlFlowBlocks(node, lView, results);
+    return findControlFlowBlocks(node, lView);
   }
 
-  return results;
+  return [];
 }
 
 /**
@@ -91,8 +88,6 @@ const deferBlockFinder: ControlFlowBlockViewFinder = ({
     const tDetails = getTDeferBlockDetails(tView, tNode);
 
     if (isTDeferBlockDetails(tDetails)) {
-      // return {lContainer, lView, tNode, tDetails};
-
       const native = getNativeByTNode(tNode, lView);
       const lDetails = getLDeferBlockDetails(lView, tNode);
 
@@ -174,7 +169,7 @@ const forLoopFinder: ControlFlowBlockViewFinder = ({
 }: ControlFlowBlockViewFinderConfig) => {
   const slot = lView[slotIdx];
 
-  if (!isRepeaterMetadata(slot)) {
+  if (!(slot instanceof RepeaterMetadata)) {
     return null;
   }
 
@@ -222,9 +217,14 @@ const CONTROL_FLOW_BLOCK_FINDERS: ControlFlowBlockViewFinder[] = [deferBlockFind
  *
  * @param node Node in which to search for blocks.
  * @param lView View within the node in which to search for blocks.
- * @param results Array to which to add blocks once they're found.
+ * @param results (Optional) Array to which to add blocks once they're found.
+ * @returns Found control flow blocks results array.
  */
-function findControlFlowBlocks(node: Node, lView: LView, results: ControlFlowBlock[]) {
+function findControlFlowBlocks(
+  node: Node,
+  lView: LView,
+  results: ControlFlowBlock[] = [],
+): ControlFlowBlock[] {
   const tView = lView[TVIEW];
 
   for (let i = HEADER_OFFSET; i < tView.bindingStartIndex; i++) {
@@ -255,6 +255,8 @@ function findControlFlowBlocks(node: Node, lView: LView, results: ControlFlowBlo
       findControlFlowBlocks(node, slot, results);
     }
   }
+
+  return results;
 }
 
 /**
@@ -318,27 +320,13 @@ function getRendererLView(lContainer: LContainer): LView | null {
   return lView;
 }
 
-/**
- * Checks if a value looks like RepeaterMetadata by duck-typing.
- * Can't use instanceof because that would require importing from control_flow.ts.
- */
-function isRepeaterMetadata(value: unknown): value is RepeaterMetadataShape {
-  return (
-    value !== null &&
-    typeof value === 'object' &&
-    'hasEmptyBlock' in value &&
-    'trackByFn' in value &&
-    typeof (value as RepeaterMetadataShape).trackByFn === 'function'
-  );
-}
-
 /**
  * Returns the string representation of the track expression.
  *
  * @param metadata Metadata containing the track function.
  * @returns
  */
-function getTrackExpression(metadata: RepeaterMetadataShape): string {
+function getTrackExpression(metadata: RepeaterMetadata): string {
   const trackByFn = metadata.trackByFn;
   if (trackByFn.name === 'ɵɵrepeaterTrackByIndex') {
     return '$index';

packages/core/src/render3/util/control_flow_types.ts

@@ -93,16 +93,6 @@ export interface ControlFlowBlockViewFinderConfig {
 /**
  * Describes a finder function that extracts `ControlFlowBlock`s from an LView.
  */
-export interface ControlFlowBlockViewFinder {
-  (config: ControlFlowBlockViewFinderConfig): ControlFlowBlock | null;
-}
-
-/**
- * Represents `RepeaterMetadata` data mirror.
- */
-export interface RepeaterMetadataShape {
-  hasEmptyBlock: boolean;
-  trackByFn: TrackByFunction<unknown>;
-  liveCollection?: LiveCollection<unknown, unknown>;
-  originalTrackByFn?: TrackByFunction<unknown>;
-}
+export type ControlFlowBlockViewFinder = (
+  config: ControlFlowBlockViewFinderConfig,
+) => ControlFlowBlock | null;