createReaction

createReaction creates a reaction that invalidates once for each call to the returned tracking function.

Import

import { createReaction } from "solid-js";

Type

function createReaction(
  onInvalidate: () => void,
  options?: { name?: string }
): (tracking: () => void) => void;

Parameters

onInvalidate

• Type: () => void
• Required: Yes

Callback invoked when the tracked computation is invalidated.

options

name

• Type: string

Debug name used by development tooling.

Return value

• Type: (tracking: () => void) => void

Returns a function that executes tracking and records its dependencies for a single invalidation.

Behavior

• Each call to the returned function records dependencies read during tracking.
• onInvalidate runs untracked on the first change to any recorded dependency.
• On the server, the returned function just executes tracking.

Examples

Track a signal for one invalidation

import { createReaction, createSignal } from "solid-js";

const [value, setValue] = createSignal("start");

const track = createReaction(() => console.log("changed"));

track(() => value());

setValue("end"); // logs "changed"
setValue("final"); // no-op until track() runs again

Related

• createEffect
• createComputed