How can I implement a custom event emitter in JavaScript?

How can I implement a custom event emitter in JavaScript?

To implement a custom event emitter, you can create a class that manages event listeners and emits events.

Can you show me a simple code example?

Sure! Here's a basic implementation:

class EventEmitter {
    constructor() {
        this.events = {};
    }

    on(event, listener) {
        if (!this.events[event]) {
            this.events[event] = [];
        }
        this.events[event].push(listener);
    }

    emit(event, ...args) {
        if (this.events[event]) {
            this.events[event].forEach(listener => listener(...args));
        }
    }
}

This class allows you to register listeners and emit events.

How do I use this EventEmitter class?

You can use it like this:

const emitter = new EventEmitter();

emitter.on('eventName', (data) => {
    console.log('Event received:', data);
});

emitter.emit('eventName', { key: 'value' });

This will log 'Event received: { key: 'value' }' when the event is emitted.

What if I want to remove a listener?

You can add a removeListener method to your EventEmitter class to handle that. Would you like to see how?