storik

Storik is very tiny (~ 400 bytes!) store with subscription. It is based on observables principles and inspired by writable stores from Svelte package.

Usage

Simple case

import storik from 'storik';

const mystore = storik('some initial value');
....
const unsubscribe = mystore.subscribe( value => console.log('Hey! My value just changed:',value));
// Hey! My value just changed: some initial value
....
mystore.set('new value');  
// Hey! My value just changed: new value
....
mystore.update(value => value.toUpperCase());  
// Hey! My value just changed: NEW VALUE
....
unsubscribe();

First and lust subscribers

import storik from 'storik';

const mystore = storik(123,()=>{
    console.log("I run every time when number of subscribers changes from 0 to 1");
    return ()=>console.log("I run every time when number of subscribers changes from 1 to 0");
});
....
const un1 = mystore.subscribe( value => console.log("I am subscriber #1"));
// I run every time when number of subscribers changes from 0 to 1
// I am subscriber #1
....
const un2 = mystore.subscribe( value => console.log("I am subscriber #2"));
// I am subscriber #2
...
un1();
//<nothing>
un2();
//I run every time when number of subscribers changes from 1 to 0
....
const un3 = mystore.subscribe( value => console.log("I am subscriber #3"));
// I run every time when number of subscribers changes from 0 to 1
// I am subscriber #3

Custom store

You can create the store with very complex behaviour, just use store's methods subscribe,set and update as bricks.

import storik from 'storik';

function counterStore(){
    const {subscribe,set,update} = storik(0);

    return {
        subscribe,
        increment: () => update(value => value + 1),
        decrement: () => update(value => value - 1),
        reset: () => set(0)
    }
}
...

const counter = counterStore();

counter.subscribe(value => console.log('Counter value is',value));
//Counter value is 0
counter.increment();
//Counter value is 1
counter.increment();
//Counter value is 2
counter.reset();
//Counter value is 0
counter.decrement();
//Counter value is -1

API

Storik initialization

storik(initial,on_first_subscriber)

Function, which returns the store object. Returns Storik store object First param is initial value of the new store. Second param is optional. It is a callback-function, which will be called each time when number of subscribers changes from 0 to 1. This function get set(value) method as argument, which allows to set new store value. It May return other callback-function, which will be called when number of subscribers will change from 1 to 0.

Storik store object

subscribe(callback)

Register the store subscription. Whenever store's value will change, callback function will be called with value passed. At the start of subscription callback function will be called once.

get()

Get current value of the store.

set(value)

Set new value of the store. Will triger all subscribers.

update(callback)

Allows to update store value. callbak function gets current value as a parameter and MUST return changed value, which be set as new store value. Will triger all subscribers.