Remove the defaultImpl parameter from Closure Delegates helper methods.

Callers are instead encouraged to explicitly check the number of registered delegates, or use the nullish coalescing operator on the result of the helper method as in `callFirst(delegates, (d) => ...) ?? defaultValue`

RELNOTES[INC]: Remove the `defaultImpl` parameter from Closure Delegates helper methods.

PiperOrigin-RevId: 510550303
Change-Id: Ia405b30a0bab5b8bf995b05870f74ce933252d1f

Author: Closure Team

closure/goog/delegate/delegates.js

@@ -18,13 +18,12 @@ goog.module('goog.delegate.delegates');
  * Calls the first delegate, or returns undefined if none are given.
  * @param {!Array<T>} delegates
  * @param {function(T): R} mapper
- * @param {function(): (R|undefined)=} defaultImpl
  * @return {R|undefined}
  * @template T, R
  */
-exports.callFirst = (delegates, mapper, defaultImpl = undefined) => {
+exports.callFirst = (delegates, mapper) => {
   if (delegates.length === 0) {
-    return defaultImpl ? defaultImpl() : undefined;
+    return undefined;
   }
   return mapper(delegates[0]);
 };
@@ -35,36 +34,27 @@ exports.callFirst = (delegates, mapper, defaultImpl = undefined) => {
  * undefined if no such element is found.
  * @param {!Array<T>} delegates
  * @param {function(T): R|undefined} mapper
- * @param {function(): (R|undefined)=} defaultImpl
  * @return {R|undefined}
  * @template T, R
  */
-exports.callUntilDefinedAndNotNull =
-    (delegates, mapper, defaultImpl = undefined) => {
-      if (delegates.length === 0) {
-        return defaultImpl ? defaultImpl() : undefined;
-      }
-      for (const delegate of delegates) {
-        const result = mapper(delegate);
-        if (result != null) return result;
-      }
-      return undefined;
-    };
+exports.callUntilDefinedAndNotNull = (delegates, mapper) => {
+  for (const delegate of delegates) {
+    const result = mapper(delegate);
+    if (result != null) return result;
+  }
+  return undefined;
+};
 
 
 /**
  * Calls delegates until one returns a truthy result.  Returns false if no such
  * element is found.
  * @param {!Array<T>} delegates
  * @param {function(T): R} mapper
- * @param {function(): (R|boolean)=} defaultImpl
  * @return {boolean|R}
  * @template T, R
  */
-exports.callUntilTruthy = (delegates, mapper, defaultImpl = undefined) => {
-  if (delegates.length === 0) {
-    return defaultImpl ? defaultImpl() : false;
-  }
+exports.callUntilTruthy = (delegates, mapper) => {
   for (const delegate of delegates) {
     const result = mapper(delegate);
     if (result) return result;

closure/goog/delegate/delegates_test.js

@@ -37,37 +37,6 @@ testSuite({
     assertCallCounts(1, 1, 1, 0);
   },
 
-  testWithDelegatesRegistered_defaultFunctionsAreNotCalled() {
-    const funcs = [
-      () => 'non-default',
-    ];
-
-    assertEquals('non-default', delegates.callFirst(funcs, f => f(), () => {
-      throw new Error('Default should not have been called');
-    }));
-    assertEquals(
-        'non-default',
-        delegates.callUntilDefinedAndNotNull(funcs, f => f(), () => {
-          throw new Error('Default should not have been called');
-        }));
-    assertEquals(
-        'non-default', delegates.callUntilTruthy(funcs, f => f(), () => {
-          throw new Error('Default should not have been called');
-        }));
-  },
-
-  testWithNoDelegatesRegistered_defaultFunctionsAreCalled() {
-    const funcs = [];
-
-    assertEquals(
-        'default', delegates.callFirst(funcs, f => f(), () => 'default'));
-    assertEquals(
-        'default',
-        delegates.callUntilDefinedAndNotNull(funcs, f => f(), () => 'default'));
-    assertEquals(
-        'default', delegates.callUntilTruthy(funcs, f => f(), () => 'default'));
-  },
-
   testResultNeverDefined() {
     const funcs = [
       recordFunction(),