README.md

jotai-sync

[Japanese]

jotai-sync is a simple library for synchronizing two Jotai atoms. It ensures that changes in one atom are reflected in the other atom automatically.

Installation

$ npx jsr add @mrsekut/jotai-sync

Usage

Here is a basic example of how to use jotai-sync to synchronize two atoms: _valueAtom and _fieldAtom.

import { atom, useAtom } from 'jotai';
import { syncAtoms, ok, ng } from '@mrsekut/jotai-sync';

// Define the two atoms
const _valueAtom = atom<number>(0);
const _fieldAtom = atom<string>('');

// Create synchronized atoms
const [valueAtom, fieldAtom] = syncAtoms<number, string>(
  _valueAtom,
  _fieldAtom,

  // value → field
  v => ok(v.toString()),

  // field → value
  field => {
    const n = parseInt(field, 10);
    return isNaN(n) ? ng('Invalid number') : ok(n);
  },
);

When synchronizing two atoms (_valueAtom and _fieldAtom):

• _valueAtom is used internally.
• _fieldAtom is used for external interactions.

By passing these atoms to syncAtoms, new valueAtom and fieldAtom are returned. These new atoms are synchronized: updating one will automatically update the other. If you need to update only one without synchronizing, refer to the original atoms (_valueAtom or _fieldAtom).

Since we are synchronizing values with different structures, we need to provide conversion functions to transform the values both ways:

• The third argument of syncAtoms converts value to field.
• The fourth argument of syncAtoms converts field to value.

Each conversion function returns a Result type. Using the ok() and ng() utility functions simplifies this process.

Contributing

Welcome

LICENSE

MIT