fixup! perf(core): allow checkNoChanges mode to be tree-shaken in p…

…roduction
angular · May 7, 2022 · ad3103a · ad3103a
1 parent 83f75f3
commit ad3103a
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Showing 3 changed files with 10 additions and 6 deletions.
diff --git a/packages/core/src/change_detection/change_detector_ref.ts b/packages/core/src/change_detection/change_detector_ref.ts
@@ -104,7 +104,7 @@ export abstract class ChangeDetectorRef {
    * Checks the change detector and its children, and throws if any changes are detected.
    *
    * Use in development mode to verify that running change detection doesn't introduce
-   * other changes.
+   * other changes. Calling it in production mode is a noop.
    */
   abstract checkNoChanges(): void;
 

diff --git a/packages/core/src/render3/instructions/shared.ts b/packages/core/src/render3/instructions/shared.ts
@@ -505,18 +505,22 @@ export function refreshView<T>(
 export function renderComponentOrTemplate<T>(
     tView: TView, lView: LView, templateFn: ComponentTemplate<{}>|null, context: T) {
   const rendererFactory = lView[RENDERER_FACTORY];
-  const normalExecutionPath = !ngDevMode || !isInCheckNoChangesMode();
+
+  // Check no changes mode is a dev only mode used to verify that bindings have not changed
+  // since they were assigned. We do not want to invoke renderer factory functions in that mode
+  // to avoid any possible side-effects.
+  const checkNoChangesMode = !!ngDevMode && isInCheckNoChangesMode();
   const creationModeIsActive = isCreationMode(lView);
   try {
-    if (normalExecutionPath && !creationModeIsActive && rendererFactory.begin) {
+    if (!checkNoChangesMode && !creationModeIsActive && rendererFactory.begin) {
       rendererFactory.begin();
     }
     if (creationModeIsActive) {
       renderView(tView, lView, context);
     }
     refreshView(tView, lView, templateFn, context);
   } finally {
-    if (normalExecutionPath && !creationModeIsActive && rendererFactory.end) {
+    if (!checkNoChangesMode && !creationModeIsActive && rendererFactory.end) {
       rendererFactory.end();
     }
   }

diff --git a/packages/core/src/render3/state.ts b/packages/core/src/render3/state.ts
@@ -184,8 +184,8 @@ const instructionState: InstructionState = {
  *
  * Necessary to support ChangeDetectorRef.checkNoChanges().
  *
- * checkNoChanges Runs only in devmode=true and verifies that no unintended changes exist in
- * the change detector or its children.
+ * The `checkNoChanges` function is invoked only in ngDevMode=true and verifies that no unintended
+ * changes exist in the change detector or its children.
  */
 let _isInCheckNoChangesMode = false;