From c740cad71c3638b2966e8435e8beb57ca7bc88dc Mon Sep 17 00:00:00 2001
From: Zhang Yi Jiang <mediumdeviation@gmail.com>
Date: Thu, 27 May 2021 15:46:23 -0700
Subject: [PATCH] [selenium-webdriver] Allow Condition.fn to return Promise<T>
 and null (#53444)

---
 types/selenium-webdriver/index.d.ts    | 6 ++++--
 types/selenium-webdriver/test/index.ts | 5 +++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/types/selenium-webdriver/index.d.ts b/types/selenium-webdriver/index.d.ts
index 06eba6afa33ad9..7dc46c5ee563da 100644
--- a/types/selenium-webdriver/index.d.ts
+++ b/types/selenium-webdriver/index.d.ts
@@ -308,6 +308,8 @@ export namespace error {
   function encodeError(err: any): {error: string, message: string};
 }
 
+type ConditionFn<T> = (webdriver: WebDriver) => T | null | Promise<T | null>;
+
 /**
  * Defines a condition for use with WebDriver's WebDriver#wait wait command.
  */
@@ -319,13 +321,13 @@ export class Condition<T> {
    *     evaluate on each iteration of the wait loop.
    * @constructor
    */
-  constructor(message: string, fn: (webdriver: WebDriver) => T);
+  constructor(message: string, fn: ConditionFn<T>);
 
   /** @return {string} A description of this condition. */
   description(): string;
 
   /** @type {function(!WebDriver): OUT} */
-  fn(webdriver: WebDriver): T;
+  fn(webdriver: WebDriver): ConditionFn<T>;
 }
 
 /**
diff --git a/types/selenium-webdriver/test/index.ts b/types/selenium-webdriver/test/index.ts
index f92bfb7b64dd6a..cc5222121e1600 100644
--- a/types/selenium-webdriver/test/index.ts
+++ b/types/selenium-webdriver/test/index.ts
@@ -524,6 +524,11 @@ function TestWebElementPromise() {
     elementPromise.then((element: webdriver.WebElement) => 'foo', (error: any) => 'bar').then((result: string) => {});
 }
 
+function testCondition() {
+    const conditionString = new webdriver.Condition<string>('message', () => Math.random() > 0.5 ? 'foo' : null);
+    const conditionStringPromise = new webdriver.Condition<string>('message', async () => Math.random() > 0.5 ? 'foo' : null);
+}
+
 declare let stringPromise: Promise<string>;
 
 function TestUntilModule() {