From b171cb7f1367a2058f01d4edfa4d8974b060d247 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20Rish=C3=B8j?= <christian@rishoj.net>
Date: Sun, 21 Jul 2024 13:46:03 +0200
Subject: [PATCH 1/4] add `leading` option for `debounce`

---
 docs/curry/debounce.mdx      | 9 +++++++++
 src/curry/debounce.ts        | 6 +++++-
 tests/curry/debounce.test.ts | 8 ++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/docs/curry/debounce.mdx b/docs/curry/debounce.mdx
index e2bd9ddb..26320460 100644
--- a/docs/curry/debounce.mdx
+++ b/docs/curry/debounce.mdx
@@ -32,6 +32,15 @@ debounce Invocations: x x x x - - - - - - - - x x x x x x x x x x - - - - - - -
 Source Invocations: - - - - - - - - - - x - - - - - - - - - - - - - - - - - x - - - - -
 ```
 
+The `leading` option decides whether the source function is called on the first
+invocation of the throttle function or not.
+
+```sh
+Time: 0ms - - - - 100ms - - - - 200ms - - - - 300ms - - - - 400ms - - - -
+debounce Invocations: x x x x - - - - - - - - x x x x x x x x x x - - - - - - - - - - - -
+Source Invocations: x - - - - - - - - - x - - - - - - - - - - - - - - - - - x - - - - -
+```
+
 ### Cancel
 
 The function returned by `debounce` has a `cancel` method that when called will permanently stop the source function from being debounced.
diff --git a/src/curry/debounce.ts b/src/curry/debounce.ts
index a09f815e..6cbd0c39 100644
--- a/src/curry/debounce.ts
+++ b/src/curry/debounce.ts
@@ -37,7 +37,7 @@ export type DebounceFunction<TArgs extends any[]> = {
  * ```
  */
 export function debounce<TArgs extends any[]>(
-  { delay }: { delay: number },
+  { delay, leading = false }: { delay: number; leading?: boolean },
   func: (...args: TArgs) => any,
 ): DebounceFunction<TArgs> {
   let timer: unknown = undefined
@@ -50,6 +50,10 @@ export function debounce<TArgs extends any[]>(
         active && func(...args)
         timer = undefined
       }, delay)
+      if (leading) {
+        func(...args)
+        leading = false
+      }
     } else {
       func(...args)
     }
diff --git a/tests/curry/debounce.test.ts b/tests/curry/debounce.test.ts
index 1c0d2bd5..1e3c58da 100644
--- a/tests/curry/debounce.test.ts
+++ b/tests/curry/debounce.test.ts
@@ -75,4 +75,12 @@ describe('debounce', () => {
     vi.advanceTimersByTime(delay + 10)
     expect(mockFunc).toHaveBeenCalledTimes(0)
   })
+
+  test('executes the function immediately on the first invocation of the debounce function when set `leading` to true', async () => {
+    func = _.debounce({ delay: delay, leading: true }, mockFunc)
+    runFunc3Times()
+    expect(mockFunc).toHaveBeenCalledTimes(1)
+    vi.advanceTimersByTime(delay + 10)
+    expect(mockFunc).toHaveBeenCalledTimes(2)
+  })
 })

From 862ac0d83a4abfec5e1df3b7abf2e042a91730ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20Rish=C3=B8j?= <christian@rishoj.net>
Date: Sun, 11 Aug 2024 18:10:57 +0200
Subject: [PATCH 2/4] chore: add jsdoc suggested by @MarlonPassos-git

---
 src/curry/debounce.ts | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/curry/debounce.ts b/src/curry/debounce.ts
index 6cbd0c39..ffa9fe91 100644
--- a/src/curry/debounce.ts
+++ b/src/curry/debounce.ts
@@ -37,7 +37,16 @@ export type DebounceFunction<TArgs extends any[]> = {
  * ```
  */
 export function debounce<TArgs extends any[]>(
-  { delay, leading = false }: { delay: number; leading?: boolean },
+  { delay, leading = false }: { 
+    delay: number;
+    /**
+     * Decides whether the source function is called on the first
+     * invocation of the throttle function or not
+     * 
+     * @default false
+     */
+    leading?: boolean
+  },
   func: (...args: TArgs) => any,
 ): DebounceFunction<TArgs> {
   let timer: unknown = undefined

From 06c5b74d2862ed274f50483ffc545d9dd6c02208 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20Rish=C3=B8j?= <christian@rishoj.net>
Date: Sun, 11 Aug 2024 18:12:30 +0200
Subject: [PATCH 3/4] fix: wording

---
 tests/curry/debounce.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/curry/debounce.test.ts b/tests/curry/debounce.test.ts
index 1e3c58da..7d9c8192 100644
--- a/tests/curry/debounce.test.ts
+++ b/tests/curry/debounce.test.ts
@@ -76,7 +76,7 @@ describe('debounce', () => {
     expect(mockFunc).toHaveBeenCalledTimes(0)
   })
 
-  test('executes the function immediately on the first invocation of the debounce function when set `leading` to true', async () => {
+  test('executes the function immediately on the first invocation when `leading` is `true`', async () => {
     func = _.debounce({ delay: delay, leading: true }, mockFunc)
     runFunc3Times()
     expect(mockFunc).toHaveBeenCalledTimes(1)

From 718ded5ef260d7c6f21a14dbfebd4738573a8e11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20Rish=C3=B8j?= <christian@rishoj.net>
Date: Sun, 11 Aug 2024 18:16:34 +0200
Subject: [PATCH 4/4] style: format

---
 src/curry/debounce.ts | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/curry/debounce.ts b/src/curry/debounce.ts
index ffa9fe91..70614c2a 100644
--- a/src/curry/debounce.ts
+++ b/src/curry/debounce.ts
@@ -37,12 +37,15 @@ export type DebounceFunction<TArgs extends any[]> = {
  * ```
  */
 export function debounce<TArgs extends any[]>(
-  { delay, leading = false }: { 
-    delay: number;
+  {
+    delay,
+    leading = false,
+  }: {
+    delay: number
     /**
      * Decides whether the source function is called on the first
      * invocation of the throttle function or not
-     * 
+     *
      * @default false
      */
     leading?: boolean