# @solid-primitives/trigger
[](https://bundlephobia.com/package/@solid-primitives/trigger)
[](https://www.npmjs.com/package/@solid-primitives/trigger)
[](https://github.com/solidjs-community/solid-primitives#contribution-process)
A set of primitives based on Solid signals, used to trigger computations.
- [`createTrigger`](#createtrigger) - Set listeners in reactive computations and then trigger them when you want.
- [`createTriggerCache`](#createtriggercache) - Creates a cache of triggers that can be used to mark dirty only specific keys.
## Installation
```bash
npm install @solid-primitives/trigger
# or
yarn add @solid-primitives/trigger
# or
pnpm add @solid-primitives/trigger
```
## `createTrigger`
Set listeners in reactive computations and then trigger them when you want.
### How to use it
```ts
import { createTrigger } from "@solid-primitives/trigger";
const [track, dirty] = createTrigger();
createEffect(() => {
track();
// ...
});
// later
dirty();
```
## `createTriggerCache`
Creates a cache of triggers that can be used to mark dirty only specific keys.
Cache is a `Map` or `WeakMap` depending on the `mapConstructor` argument. (default: `Map`)
If `mapConstructor` is `WeakMap` then the cache will be weak and the keys will be garbage collected when they are no longer referenced.
Trigger signals added to the cache only when tracked under a computation,
and get deleted from the cache when they are no longer tracked.
### How to use it
`track` and `dirty` are called with a `key` so that each tracker will trigger an update only when his individual `key` would get marked as dirty.
```ts
import { createTriggerCache } from "@solid-primitives/trigger";
const map = createTriggerCache();
createEffect(() => {
map.track(1);
// ...
});
// later
map.dirty(1);
// this won't cause an update:
map.dirty(2);
```
### Triggering all keys
`dirtyAll` will trigger all keys in the cache.
```ts
const [track, _dirty, dirtyAll] = createTriggerCache();
createEffect(() => {
track(1);
// ...
});
// later (will trigger the update)
dirtyAll();
```
### Weak version
`createTriggerCache` constructor can take a `WeakMap` constructor as an argument. This will create a `WeakMap` of triggers instead of a `Map`.
```ts
const map = createTriggerCache
