# Use the event bus

Squide provides a built-in event bus so that modules and other parts of a modular application can communicate in a loosely coupled way.

For more details, refer to the useEventBusListener and useEventBusDispatcher reference documentation.

# Add an event listener

Register a function that will be invoked each time the specified event is dispatched:

import { useCallback } from "react";
import { useEventBusListener } from "@squide/firefly";

const handleFoo = useCallback((data, context) => {
    // Do something...
}, []);

// Listen to every "foo" events.
useEventBusListener("foo", handleFoo);

# Add an event listener that will be invoked once

Register a function that will be invoked once, and then automatically unregisters itself:

import { useCallback } from "react";
import { useEventBusListener } from "@squide/firefly";

const handleFoo = useCallback((data, context) => {
    // Do something...
}, []);

// Listen to the first "foo" event.
useEventBusListener("foo", handleFoo, { once: true };

# Dispatch an event 

import { useEventBusDispatcher } from "@squide/firefly";

const dispatch = useEventBusDispatcher();

// Dispatch a "foo" event with a "bar" payload.
dispatch("foo", "bar");