Usage no npm install needed!

<script type="module">
  import jetstate from 'https://cdn.skypack.dev/jetstate';
</script>

README

jetstate

state managment

install

npm i jetstate --save

use

import { init, state } from 'jetstate';

/**
 * initial new state
 */
init({
  name: 'time',
  defaultValue: new Date().getTime(), 
  willUpdate: (previousValue, nextValue) => {
    console.log('willUpdate', previousValue, nextValue);
  },
  shouldUpdate: (previousValue, nextValue) => {
    if (typeof nextValue 'number') return true;
    else return false        
  },
  didUpdate: value => {
    console.log('didUpdate', value);
  }
});

var time = state.time;

//with this code, willUpdate is run and then didUpdate is run
state.time = new Date().getTime();