# reactive-signals

> JS Library for reactive and asynchronous programming

Latest version **2.0.1** (published 2021-05-09) · ISC license · 0 weekly downloads

## Install

```sh
npm install reactive-signals
pnpm add reactive-signals
yarn add reactive-signals
bun add reactive-signals
```

## Health

**Score 20/100 (F)** — status: abandoned.

Positive: esm support; no vulnerabilities.

Warnings: low downloads; no types.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 2.0.1 |
| Published | 2021-05-09 |
| First published | 2020-01-24 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | ESM + CommonJS |
| Dependencies | 0 |
| Unpacked size | 13 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Maintainers | peterekepeter |

## Links

- npm: https://www.npmjs.com/package/reactive-signals
- npm.io page: https://npm.io/package/reactive-signals

## Recent versions

- 2.0.1 (latest) — 2021-05-09
- 2.0.0 — 2021-05-09
- 1.0.1 — 2020-06-03
- 1.0.0 — 2020-01-24

## README

# reactive-signals

This is a lightweight library which is all about reactive and asynchronous programming.

Your primitive is a signal, it can hold one value at a time:

```javascript
const { createSignal } = require('reactive-signals');
const signal = createSignal();
signal.value = 42;
```

When a value is changed, you can be notified of the change:

```javascript

const signal = createSignal();
let triggerCount = 0;
signal.event(() => triggerCount++);
signal.value = 42; // trigger count changes from 0 to 1
```

Sometimes the object listening to the signal might be detroyed,
in this case you will need to unsubscribe from the signal.

```javascript
const signal = createSignal();
let triggerCount = 0;
const subscription = signal.event(() => triggerCount++);
signal.value = 42; // triggerCount changes from 0 to 1
subscription.cancel();
signal.value = 13; // triggerCount stays 1 because we unsubscribed
```

There are a few more things which help manage compelxity and improve performance,
signals will detect if the value changes and only trigger 
an event if the value has indeed changed:

```javascript
const signal = createSignal();
let triggerCount = 0;
signal.value = 13;
signal.event(() => triggerCount++);
signal.value = 13; // no change
signal.value = 42; // triggerCount changes to 1
signal.value = 42; // triggerCount stays 1
```

You can supply your own object comparer:

```javascript
const signal = createSignal({x:1,y:2}, {
    equals: (a,b) => a.x === b.x && a.y === b.y
});
let triggerCount = 0;
signal.event(() => triggerCount++);
signal.value = {x:1, y:2}; // no change
signal.value = {x:1, y:3}; // triggerCount changes to 1
signal.value = {x:1, y:3}; // triggerCount stays 1
```

## other features

Best check out the code. 
[Typedef file contains additional documentation](https://github.com/peterekepeter/reactive-signals/blob/master/lib/signal.d.ts)
[Tests cover additional use cases](https://github.com/peterekepeter/reactive-signals/tree/master/test)

---
_Source: https://npm.io/package/reactive-signals · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._