@tiny-lit/store

A framework-agnostic centralized state management based on the Vuex pattern

Installation

To install with npm

npm i --save @tiny-lit/store

or with yarn

yarn add @tiny-lit/store

Introduction

A store uses actions and mutations to bring changes to the state.

Actions

Action handlers are pure functions that accepts the store class and data as arguments. They can contain async operations and MUST NOT directly mutate the state, but they may commit mutations.

type ActionHandler = (store: StoreInterface, data: any) => void;

Mutations

Mutations handlers area responsible of muting the state. The first parameter is the state object and the second is the data. The returned object is the new state.

type MutationHandler = (state?: any, data?: any) => object;

Plugins

A plugin is a function, called just after the initialization of the store, that receive the store instance in the first argument.

type PluginHandler = (store: StoreInterface) => void;

Getting started

Options

You can create a store using createStore function passing a configuration object.

These are the options you can specify in the configuration:

• actions an object containing the actions
• mutations and object containing the mutations
• initialState the initial state of your application
• plugins and array of plugins

Methods

• subscribe Registers a handler to the store listening for changes. It will return an unsubscribe function.

subscribe(callback: (state: any, mutation?: Mutation) => void) => Function

• commit Applies the mutation provided.

commit(type: string, data:any) => object
commit(mutation: {
    type: string;
    data: any;
}) => object

Properties

• mutations A map of the registered mutations
• actions A map of the registered actions
• state The state

Example

This is a basic example on how to create a store:

import { createStore } from '@tiny-lit/store';

const consolePlugin = store => store.subscribe(console.log);

const myStore = createStore({
    config = {
        actions: {
            incrementCounter(store, data) {
                store.commit('setCount', store.state + data)
            },
            decrementCounter(store, data) {
                store.commit('setCount', store.state - data)
            },
            asyncIncrement(store) {
                store.commit('setCount', 0);
                fetch('https://www.example.com')
                    .then(response => response.json())
                    .then(({ counter }) => {
                        store.commit('setCount', counter);
                    })
            }
        },
        mutations: {
            setCount(state, data) {
                return {
                    count: data
                };
            }
        },
        initialState: {
            count: 0
        },
        plugins: [consolePlugin]
    }
})

Use with custom elements

Provider

To use the store in conjuction with your custom elements, you need to create a Provider element for your store.

To do that, simply create an element extending the StoreProvider class and implementing a getter named config that will return your store configuration object.

Example

import { StoreProvider } from '@tiny-lit/store';

class MyStore extends StoreProvider {
    static get is() {
        return 'my-store';
    }

    get config() {
        return {
            // your config goes here
        };
    }
}
customElements.define(MyStore.is, MyStore);

Consumer

Now that you have a store provider, you need to connect your custom elements to it. Using the withStore mixin, it will subscribe/unsubscribe your elements to the store on connect/disconnected callbacks.

These are the lifecycle callbacks you can implement:

• onStoreConnect Called when the element connected to a store

onStoreConnect() => void

• onStateChange Called everytime the state changed

onStateChange(newState: any) => void

In addition, your element will implement a dispatch method for triggering changes. It is essentially a proxy to store.dispatch, the only difference is that using the withStore mixin everything is based on DOM events.

dispatch(type: string, data?: any) => void;

Note that if you don't provide a Provider, your element will continue to works as usual.

Example

import { withStore } from '@tiny-lit/store';

class MyCounter extends withStore(HTMLElement) {
    constructor() {
        super();
        this.count = 0;
    }

    onStateChange(state) {
        if (this.count !== state.count) {
            this.count = state.count;

            this.update();
        }
    }

    static get is() { return 'my-counter'; }

    update() {
        this.innerText = `Count: ${this.count}`;
    }
}
customElements.define(MyCounter.is, MyCounter);

class MyButton extends withStore(HTMLElement) {
    constructor() {
        super();
        
        this.addEventListener('click', () => {
            this.dispatch('increment');
        })
    }

    static get is() { return 'my-button'; }
}
customElements.define(MyButton.is, MyButton);

A DOM Example

<my-store>
    <my-consumer></my-consumer>
    <my-button>Click to increment</my-button>
</my-store>