Synapses

![Banner](.github/media/synapses-banner.png)

Event-driven Alternative to React Context

```shell npm i @nucleoidjs/synapses ``` Synapses is an alternative to React Context with event-driven style communication that helps to build loosely coupled components. ### How it works? Subscribers are registered an event with the custom hook `useEvent(eventType, initialValue)`, once publisher posts an event and its payload, Synapses asynchronously sends the event to subscribed components and subscribed components will eventually be re-rendered with fresh data. Example: ```javascript import { publish } from "@nucleoidjs/synapses"; const PublishComponent = () => { return ( ); }; ``` ```javascript import { useEvent } from "@nucleoidjs/synapses"; const Component1 = () => { const [event] = useEvent("BUTTON_CLICKED", { number: 10 }); return

{event.number}

; }; ``` ```javascript import { useEvent } from "@nucleoidjs/synapses"; const Component2 = () => { const [event] = useEvent("BUTTON_CLICKED", { string: "blue" }); return

{event.string}

; }; ```

The complete sample project is [here](./sample). ### Stateless Handling Synapses supports stateless components with caching last published payload for the event type, so that if the component is re-rendered, it won't lose the payload. For example, Component 3 in this example is not re-rendered yet, but Synapses holds the last payload for the event type, and once the component is rendered, it returns the payload instead of initial value. Synapses Diagram

## Event-driven Architecture Event-driven Architecture is commonly used in Microservices systems that pretty much targets similar problem; loose coupling. This style of architecture require middleware like Kafka, RabbitMQ etc. and we are trying to adopt the very same idea to React.js, of course with some modification such as "Stateless Handling". ## API #### `const [ event ] = useEvent ( eventType , initialValue )` React Hook is to subscribe an event. If there is no event posted yet, it returns `initialValue`, otherwise, returns last published payload for the event type from cache. #### `publish ( eventType, payload )` Publish function to post ane event and its payload. #### `subscribe ( type , callback )` Subscribe function acts like `useEvent` for non-React JavaScript.