nibstate

nibstate is an attempt to make the smallest and easiest to learn state management solution. As opposed to learning complex concepts like "Observables" or "Reactive Programming" or "Reducers", nibs provides a single function which boxes up a value and - if the value gets re-assigned - anything listening to it will update.

Installation

$ npm install --save nibstate

Usage

The main export is nib, which lets you box a value into a "Nib". You can then call next(fn), and fn will be called at-most-once: the next time the nib changes value:

import {nib, get, set} from 'nibstate'

const myState = nib('foo')
get(myState) // 'foo'
myState.value // 'foo'

myState.next(console.log)

set(myState, 'bar') // you can also use `myState.value = 'bar'`
// "bar" will be logged to the console

nibs can be derived from other nibs by passing a function, which is given a special version of get that allows for automatic updating:

import {nib, get, set} from 'nibstate'

const myState = nib('hello')

const myStateUpper = nib(get => get(myState).toUpperCase())
const myStateLength = nib<number>(get => get(myState).length)

get(myState) // 'hello'
get(myStateUpper) // 'HELLO'
get(myStateLength) // 5

set(myState, 'goodbye')

get(myState) // 'goodbye'
get(myStateUpper) // 'GOODBYE'
get(myStateLength) // 7

nibs can be of any value, and they can be derived from any value, so for example you could have a function which fetches the JSON of a URL of a previous nib, like so:

import {nib, get, set} from 'nibstate'
import type {Person} from './my-api/types'

const initials = nib<string>('A')

const url = nib<string>(get => `https://example.com/api/people.json?initials=${get(initials)}`)

const people = nib<Promise<Person[]>>(async get => {
  const res = await fetch(get(url))
  const json = await res.json()
  return json.data.people
})

const givenNames = nib<Promise<string[]>>(async get => {
  const results = await get(people)
  return results.map(person => person.givenName)
})

const peopleCount = nib<Promise<number>>(async get => {
  const results = await get(people)
  return results.length
})

console.log(await get(givenNames)) // ['Aki', 'Alex', 'Ali', 'Azriel']
console.log(await get(peopleCount)) // 4

initials.value = 'B'

console.log(await get(givenNames)) // ['Baily', 'Byrd', 'Bo', 'Brit', 'Bernie']
console.log(await get(peopleCount)) // 5

If you want to subscribe to all changes of a Nib, you can for await them:

import {nib} from 'nibstate'

const tick = nib(0)

function incr() {
  tick.value += 1
  setTimeout(incr, 1000)
}
setTimeout(incr, 1000)

for await(const t of tick) {
  console.log(t)
}
// Console logs:
// 1
// 2
// 3
// ... and so on

Inspiration & Credits

nibs take some inspiration from "atoms" in libraries like Recoil and Jotai. nibs offer similar API surface, but are modelled more closely from Observables (specifically, mini-observable)