fix(@angular-devkit/build-angular): allow classes with pure annotated static properties to be optimized

packages/angular_devkit/build_angular/src/babel/plugins/adjust-static-class-members.ts

@@ -56,6 +56,33 @@ export function getKeywords(): Iterable<string> {
   return ['class'];
 }
 
+/**
+ * Determines whether a property and its initializer value can be safely wrapped in a pure
+ * annotated IIFE. Values that may cause side effects are not considered safe to wrap.
+ * Wrapping such values may cause runtime errors and/or incorrect runtime behavior.
+ *
+ * @param propertyName The name of the property to analyze.
+ * @param assignmentValue The initializer value that will be assigned to the property.
+ * @returns If the property can be safely wrapped, then true; otherwise, false.
+ */
+function canWrapProperty(propertyName: string, assignmentValue: NodePath): boolean {
+  if (angularStaticsToWrap.has(propertyName)) {
+    return true;
+  }
+
+  const { leadingComments } = assignmentValue.node as { leadingComments?: { value: string }[] };
+  if (
+    leadingComments?.some(
+      // `@pureOrBreakMyCode` is used by closure and is present in Angular code
+      ({ value }) => value.includes('#__PURE__') || value.includes('@pureOrBreakMyCode'),
+    )
+  ) {
+    return true;
+  }
+
+  return assignmentValue.isPure();
+}
+
 /**
  * Analyze the sibling nodes of a class to determine if any downlevel elements should be
  * wrapped in a pure annotated IIFE. Also determines if any elements have potential side
@@ -140,7 +167,7 @@ function analyzeClassSiblings(
     if (angularStaticsToElide[propertyName]?.(assignmentValue)) {
       nextStatement.remove();
       --i;
-    } else if (angularStaticsToWrap.has(propertyName) || assignmentValue.isPure()) {
+    } else if (canWrapProperty(propertyName, assignmentValue)) {
       wrapStatementPaths.push(nextStatement);
     } else {
       // Statement cannot be safely wrapped which makes wrapping the class unneeded.

packages/angular_devkit/build_angular/src/babel/plugins/adjust-static-class-members_spec.ts

@@ -182,7 +182,7 @@ describe('adjust-static-class-members Babel plugin', () => {
     `);
   });
 
-  it('does wrap not class with only side effect fields', () => {
+  it('does wrap not default exported class with only side effect fields', () => {
     testCaseNoChange(`
       export default class CustomComponentEffects {
         constructor(_actions) {
@@ -194,6 +194,75 @@ describe('adjust-static-class-members Babel plugin', () => {
     `);
   });
 
+  it('does wrap not class with only side effect fields', () => {
+    testCaseNoChange(`
+      class CustomComponentEffects {
+        constructor(_actions) {
+          this._actions = _actions;
+          this.doThis = this._actions;
+        }
+      }
+
+      CustomComponentEffects.someFieldWithSideEffects = console.log('foo');
+    `);
+  });
+
+  it('wraps class with pure annotated side effect fields', () => {
+    testCase({
+      input: `
+        class CustomComponentEffects {
+          constructor(_actions) {
+            this._actions = _actions;
+            this.doThis = this._actions;
+          }
+        }
+        CustomComponentEffects.someFieldWithSideEffects = /*#__PURE__*/ console.log('foo');
+      `,
+      expected: `
+        let CustomComponentEffects = /*#__PURE__*/ (() => {
+          class CustomComponentEffects {
+            constructor(_actions) {
+              this._actions = _actions;
+              this.doThis = this._actions;
+            }
+          }
+
+          CustomComponentEffects.someFieldWithSideEffects = /*#__PURE__*/ console.log('foo');
+          return CustomComponentEffects;
+        })();
+      `,
+    });
+  });
+
+  it('wraps class with closure pure annotated side effect fields', () => {
+    testCase({
+      input: `
+        class CustomComponentEffects {
+          constructor(_actions) {
+            this._actions = _actions;
+            this.doThis = this._actions;
+          }
+        }
+        CustomComponentEffects.someFieldWithSideEffects = /* @pureOrBreakMyCode */ console.log('foo');
+      `,
+      expected: `
+        let CustomComponentEffects = /*#__PURE__*/ (() => {
+          class CustomComponentEffects {
+            constructor(_actions) {
+              this._actions = _actions;
+              this.doThis = this._actions;
+            }
+          }
+
+          CustomComponentEffects.someFieldWithSideEffects =
+            /* @pureOrBreakMyCode */
+            console.log('foo');
+          return CustomComponentEffects;
+        })();
+      `,
+    });
+  });
+
   it('wraps exported class with a pure static field', () => {
     testCase({
       input: `