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A small & dependency free reactive state management library inspired by Solidjs and Recoiljs.

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Olian04/simply-reactive

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Latest released version Minified and gzipped bundle size Type support Downloads from NPM Downloads from JSDeliver Build status of main branch Code percentage covered by tests on main branch MIT licensed

simply-reactive

Simply-reactive is a small & dependency free reactive state management library inspired by Solidjs and Recoiljs.

Installation

NPM

npm i simply-reactive

import { createAtom, createEffect, createSelector } from 'simply-reactive';

CDN

ESM

<script type="module">
  import {
    createAtom,
    createEffect,
    createSelector,
  } from 'https://cdn.jsdelivr.net/npm/simply-reactive';
</script>

UMD

<script src="https://cdn.jsdelivr.net/npm/simply-reactive/cdn/umd.js"></script>
<script>
  const { createAtom, createEffect, createSelector } = simplyReactive;
</script>

Demos

Documentation

Simply-reactive provides three reactive primitives:

  • Atoms are single pieces of reactive state.
  • Selectors are pieces of derived reactive state.
  • Effects are side effects produced by changes to the reactive graph.

Simply-reactive also provides four reactive composites:

  • Groups are atoms containing collections of reactive primitives or other reactive composites.
  • Effect Groups are collections of effects used for enabeling and disabeling multiple effects at once.
  • Resources are selectors specifically optimized for data fetching.
  • External Selectors are selectors specifiacally optimized for interfacing with other reactive systems.

Atom

Atoms are single pieces of reactive state.

const Count = createAtom({
  default: 0,
});
Count.set(1);
console.log(`Count: ${Count.get()}`);

Selector

Selectors are pieces of derived reactive state.

const DoubleCount = createSelector({
  get: () => {
    return Count.get() * 2;
  },
});
console.log(`Count: ${DoubleCount.get()}`);

Effect

Effects are side effects produced by changes to the reactive graph.

createEffect(() => {
  console.log(`${DoubleCount.get()} is twice as big as ${Count.get()}`);
});

setInterval(() => {
  Count.set((c) => c + 1);
}, 1000);

Group

Groups are atoms containing collections of reactive primitives or other reactive composites.

const CountGroup = createGroup({
  getDefault: () =>
    createAtom({
      default: 0,
    }),
});

const DoubleCountGroup = createGroup({
  getDefault: (index) =>
    createSelector({
      get: () => CountGroup.find(index).get() * 2,
    }),
});

CountGroup.find(0).set(5);
CountGroup.find(1).set(2);
console.log(DoubleCountGroup.find(0).get()); // 10
console.log(DoubleCountGroup.find(1).get()); // 4
console.log(DoubleCountGroup.find(2).get()); // 0

Effect Group

Effect Groups are collections of effects used for enabeling and disabeling multiple effects at once.

createEffectGroup([
  () => (document.getElementById('in-a').value = A.get()),
  () => (document.getElementById('in-b').value = B.get()),
  () => (document.getElementById('out-a').innerText = A.get()),
  () => (document.getElementById('out-b').innerText = B.get()),
  () => (document.getElementById('out-product').innerText = A.get() * B.get()),
]);

document.getElementById('in-a').addEventListener('change', (ev) => {
  A.set(parseInt(ev.target.value, 10));
});
document.getElementById('in-b').addEventListener('change', (ev) => {
  B.set(parseInt(ev.target.value, 10));
});

Resource

Resources are selectors specifically optimized for data fetching.

const Data = createResource({
  get: async () => fetch(...),
});

console.log(`Data after first load ${await Data.get()}`);

Data.invalidate();
console.log(`Data after second load ${await Data.get()}`);

External Selector

External Selectors are selectors specifiacally optimized for interfacing with other reactive systems.

const Name = createExternalSelector({
  default: '',
  setup: (set) => {
    document
      .querySelector('#input')
      .addEventListener('change', (ev) => set(ev.target.value));
  },
});

createEffect(() => {
  document.querySelector('#output').innerText = `Hello, ${
    Name.get() ?? 'World'
  }!`;
});