Managing State with MobX
What is MobX?
MobX is a state management library that makes it simple to connect the reactive data of your application with the UI. Its philosophy revolves around making state as transparently applicable as possible, so you can focus on the development of your application, rather than the boilerplate of managing state. MobX achieves this with concepts like observables, actions, and reactions, which ensure your UI updates efficiently and only when necessary.
Integration with Lit Elements
We enhance our Lit elements by integrating MobX for state management using the @adobe/lit-mobx plugin. This setup allows our components to reactively update whenever the state in the stores changes, without manual intervention:
- Observable stores: Define your application's state in centralized stores.
- Reactive components: Components automatically re-render when the state they depend on updates.
Why Use MobX?
In complex applications, handling data across various components becomes challenging:
- Data Redundancy: Data duplicated across components can lead to heavy maintenance and a higher risk of bugs.
- Prop Drilling: Passing data through multiple layers of components is not only tedious but also error-prone.
- Cluttered Component Trees: Components get cluttered with props that are irrelevant to their functionality, which obscures their intent.
MobX addresses these issues by allowing you to:
- Centralize State: Manage shared state outside of components in a global singleton store.
- Efficient Data Sharing: Share data between components without excessive prop passing.
- Predictable Updates: Ensure consistent updates across your application, which helps in maintaining predictable behavior.
Basic Example
// store.js
import { makeAutoObservable } from 'mobx';
class CounterStore {
count = 0;
constructor() {
makeAutoObservable(this);
}
increment() {
this.count++;
}
decrement() {
this.count--;
}
}
export const counterStore = new CounterStore();
// counter-component.js
import { LitElement, html } from 'lit';
import { counterStore } from './store';
import { observer } from '@adobe/lit-mobx';
class CounterComponent extends observer(LitElement) {
render() {
return html`
<div>Count: ${counterStore.count}</div>
<button @click=${counterStore.increment}>+</button>
<button @click=${counterStore.decrement}>-</button>
`;
}
}
customElements.define('counter-component', CounterComponent);
In this example, the CounterComponent will automatically update whenever the count property in the CounterStore changes, thanks to the reactive capabilities provided by MobX and the @adobe/lit-mobx integration.