Skip to content

[TS] Narrow types for Show utility #701

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
JoviDeCroock merged 4 commits into from
Jun 27, 2025
Merged

[TS] Narrow types for Show utility #701

Changes from 2 commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
28b028e
Narrow types for Show utility
calebeby Jun 26, 2025
2f1751b
TIL that 0n is also falsy
calebeby Jun 26, 2025
229fbbe
Use NonNullable<T>. That's what TS type narrowing does by default.
calebeby Jun 26, 2025
a1e13bf
Add changeset
JoviDeCroock Jun 27, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion packages/preact/utils/src/index.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,10 +3,12 @@ import { useSignal } from "@preact/signals";
import { Fragment, createElement, JSX } from "preact";
import { useMemo } from "preact/hooks";

type Falsy = false | 0 | 0n | "" | null | undefined;
Comment thread
calebeby marked this conversation as resolved.
Outdated

interface ShowProps<T = boolean> {
when: Signal<T> | ReadonlySignal<T>;
fallback?: JSX.Element;
children: JSX.Element | ((value: T) => JSX.Element);
children: JSX.Element | ((value: Exclude<T, Falsy>) => JSX.Element);
}

export function Show<T = boolean>(props: ShowProps<T>): JSX.Element | null {
Expand Down