Podda

Simple Reactive DataStore for JavaScript.

This is a pure JavaScript in-memory key value store for your Single Page App.(SPA) You can think this as a simple key value store with an event emitter.

This works pretty well with React (as an simple substitute for Redux/MobX), but works with anything in JavaScript.

Installation

npm install --save podda

Sample Usage

Let's subscribe to the data store and set an item.

import Podda from 'podda';

const defaults = { 'race': 'Human' };
const store = new Podda(defaults);

// Subscribe for changes
const stopSubscription = store.subscribe((data) => {
  console.log('Data:', data);
});

// Set some items.
store.set('name', 'Arunoda'); // logs => Data: { name: 'Arunoda' }
store.set('age', 99); // logs => Data: { name: 'Arunoda', age: 99 }

// stop the subscription
stopSubscription();
store.set('city', 'Colombo'); // logs nothing.

Play with this example

API

Assume we've an instance of Podda called store as defined follows:

const store = new Podda();

set

Set a value. Value could be anything which can be serialize to JSON.

store.set('key', 'value');

get

Get a value by the give key.

store.get('key');

update

Update multiple entries of the store at once. While updating, you could accept the current state of the store as well.

store.update(function(state) {
  return {
    newField: 10,
    existingField: !Boolean(existingField)
  };
});

getAll

Get all the key values pairs in the store as a map.

store.getAll();

Subscribe for the store and get an snapshot of the data of the whole store. Registered callback will be fired for everything you set something to the store.

const stop = store.subscribe((data) => {
  console.log('Data:', data);
});

// Stop the subscription when needed
stop();

Call to this method return a function where you can use that to stop the subscription.

watch

Very similar to subscribe but watch a given key instead of the all keys.

const stop = store.watch('name', (name) => {
  console.log('Name is:', name);
});

store.set('name', 'Arunoda'); // logs => Name is: Arunoda
store.set('age', 99); // logs nothing.

watchFor

Very similar to watch but watch for the value of the key as well.

const stop = store.watchFor('name', 'Arunoda', (name) => {
  console.log('Name is:', name);
});

store.set('name', 'Arunoda'); // logs => Name is: Arunoda
store.set('name', 'Matt'); // logs nothing

fire

This will be pretty useful with the watch and watchFor APIs. You could simply fire those callback, without setting an item to the store. Hence, this has no effect on the subscribe.

const stop = store.watch('name', (name) => {
  console.log('Name is:', name);
});

store.set('name', 'Arunoda'); // logs => Name is: Arunoda
store.fire('name', 'Matt'); // logs => Name is: Matt
console.log(store.get('name')) // logs => Arunoda

registerAPI

With this, you'll be able to add new features to the store. For an example, let's say we are using toggle functionality in our store a lot. So, we can add an API for that like this:

store.registerAPI('toggle', (store, key) => {
  store.set(key, !store.get(key));
  return store.get(key);
});

// Then we can use it like this:
console.log('Toggled value for lights is:', store.toggle('lights'));

Using with React

In order to use this with React, you need to get help from a data container. React Komposer is an ideal tool for that.

Have a look at this example app.

storybook-eol/podda