fix(ivy): make defineComponent tree shakable by Closure Compiler (#26425)

PR Close #26425

packages/core/src/util.ts

@@ -96,3 +96,16 @@ export function stringify(token: any): string {
   const newLineIndex = res.indexOf('\n');
   return newLineIndex === -1 ? res : res.substring(0, newLineIndex);
 }
+
+/**
+ * Convince closure compiler that the wrapped function has no side-effects.
+ *
+ * Closure compiler always assumes that `toString` has no side-effects. We use this quirk to
+ * allow us to execute a function but have closure compiler mark the call as no-side-effects.
+ * It is important that the return value for the `noSideEffects` function be assigned
+ * to something which is retained otherwise the call to `noSideEffects` will be removed by closure
+ * compiler.
+ */
+export function noSideEffects(fn: () => void): string {
+  return '' + {toString: fn};
+}