From 10dac39d5003167278c105a1bf394ec260c4dde3 Mon Sep 17 00:00:00 2001 From: Durgesh Kumar Jha Date: Mon, 9 Nov 2026 15:12:50 +0530 Subject: [PATCH 1/2] Clarify callback-based fetcher example --- .../copy/en/declaration-files/Do's and Don'ts.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md b/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md index ce39fd28d96b..dafb214f006a 100644 --- a/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md +++ b/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md @@ -79,7 +79,7 @@ function fn(x: () => void) { ```ts /* WRONG */ interface Fetcher { - getObject(done: (data: unknown, elapsedTime?: number) => void): void; + fetchObject(done: (data: unknown, elapsedTime?: number) => void): void; } ``` @@ -93,7 +93,7 @@ it's always legal to provide a callback that accepts fewer arguments. ```ts /* OK */ interface Fetcher { - getObject(done: (data: unknown, elapsedTime: number) => void): void; + fetchObject(done: (data: unknown, elapsedTime: number) => void): void; } ``` From e984ca4e391a48ea522b38aa032a76a12bb2b8a8 Mon Sep 17 00:00:00 2001 From: Durgesh Kumar Jha Date: Mon, 9 Nov 2026 15:13:14 +0530 Subject: [PATCH 2/2] Explain callback-based fetcher return type --- .../documentation/copy/en/declaration-files/Do's and Don'ts.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md b/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md index dafb214f006a..9be03af00466 100644 --- a/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md +++ b/packages/documentation/copy/en/declaration-files/Do's and Don'ts.md @@ -97,6 +97,8 @@ interface Fetcher { } ``` +The method returns `void` because it delivers its result through the callback. The callback's `elapsedTime` parameter is non-optional because the callback is always called with that argument. + ### Overloads and Callbacks ❌ **Don't** write separate overloads that differ only on callback arity: