From 2b7681ee6c02e7442c6b6c2916ccb71824923b8c Mon Sep 17 00:00:00 2001
From: martin-badin <martin.badin@gmail.com>
Date: Thu, 16 Apr 2020 01:22:29 +0200
Subject: [PATCH] [@types/jquery] Improve type for find function (#43857)

---
 types/jquery/JQuery.d.ts     |  4 +++-
 types/jquery/index.d.ts      |  1 +
 types/jquery/jquery-tests.ts | 20 +++++++++++++++++++-
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/types/jquery/JQuery.d.ts b/types/jquery/JQuery.d.ts
index ed0147a89f..1d317a94b2 100644
--- a/types/jquery/JQuery.d.ts
+++ b/types/jquery/JQuery.d.ts
@@ -4133,7 +4133,9 @@ $( "p" )
 </html>
 ```
      */
-    find(selector_element: JQuery.Selector | Element | JQuery): this;
+    find<K extends keyof HTMLElementTagNameMap>(selector_element: K | JQuery<K>): JQuery<HTMLElementTagNameMap[K]>;
+    find<K extends keyof SVGElementTagNameMap>(selector_element: K | JQuery<K>): JQuery<SVGElementTagNameMap[K]>;
+    find<E extends HTMLElement>(selector_element: JQuery.Selector | E | JQuery<E>): JQuery<E>;
     /**
      * Stop the currently-running animation, remove all queued animations, and complete all animations for the matched elements.
      * @param queue The name of the queue in which to stop animations.
diff --git a/types/jquery/index.d.ts b/types/jquery/index.d.ts
index 2d4171320b..9b3207bc65 100644
--- a/types/jquery/index.d.ts
+++ b/types/jquery/index.d.ts
@@ -22,6 +22,7 @@
 //                 Dick van den Brink <https://github.com/DickvdBrink>
 //                 Thomas Schulz <https://github.com/King2500>
 //                 Terry Mun <https://github.com/terrymun>
+//                 Martin Badin <https://github.com/martin-badin>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
diff --git a/types/jquery/jquery-tests.ts b/types/jquery/jquery-tests.ts
index 9391596f37..10ddf26f6a 100644
--- a/types/jquery/jquery-tests.ts
+++ b/types/jquery/jquery-tests.ts
@@ -5849,14 +5849,26 @@ function JQuery() {
         }
 
         function find() {
-            // $ExpectType JQuery<HTMLElement>
+            // $ExpectType JQuery<HTMLSpanElement>
             $('p').find('span');
 
+            // $ExpectType JQuery<HTMLElement>
+            $('p').find('.class-name');
+
             // $ExpectType JQuery<HTMLElement>
             $('p').find(new HTMLElement());
 
+            // $ExpectType JQuery<HTMLSpanElement>
+            $('p').find(new HTMLSpanElement());
+
             // $ExpectType JQuery<HTMLElement>
             $('p').find($('span'));
+
+            // $ExpectType JQuery<HTMLSpanElement>
+            $('p').find($<HTMLSpanElement>('.class-name'));
+
+            // $ExpectType JQuery<HTMLSpanElement>
+            $('p').find<HTMLSpanElement>($('.class-name'));
         }
 
         function addBack() {
@@ -5897,11 +5909,17 @@ function JQuery() {
         function first() {
             // $ExpectType JQuery<HTMLElement>
             $('p').first();
+
+            // $ExpectType JQuery<HTMLSpanElement>
+            $('p').find('span').first();
         }
 
         function last() {
             // $ExpectType JQuery<HTMLElement>
             $('p').last();
+
+            // $ExpectType JQuery<HTMLSpanElement>
+            $('p').find('span').first();
         }
 
         function offsetParent() {