frontend-hamroun/dist/event-bus.js

A lightweight frontend JavaScript framework with React-like syntax

export function createEventBus() {
    const events = new Map();
    const onceHandlers = new WeakMap();
    const on = (event, handler) => {
        if (!events.has(event)) {
            events.set(event, new Set());
        }
        events.get(event).add(handler);
        // Return a function to remove this handler
        return () => off(event, handler);
    };
    const once = (event, handler) => {
        // Create a wrapper that will call the handler and remove itself
        const onceWrapper = (...args) => {
            off(event, onceWrapper);
            handler(...args);
        };
        // Store the mapping between the original handler and the wrapper
        onceHandlers.set(handler, onceWrapper);
        // Register the wrapper
        return on(event, onceWrapper);
    };
    const off = (event, handler) => {
        // If no handler is provided, remove all handlers for the event
        if (!handler) {
            events.delete(event);
            return;
        }
        // Check if it's a once handler wrapper
        const wrappedHandler = onceHandlers.get(handler);
        const handlerToRemove = wrappedHandler || handler;
        if (events.has(event)) {
            events.get(event).delete(handlerToRemove);
            // Clean up empty event sets
            if (events.get(event).size === 0) {
                events.delete(event);
            }
        }
    };
    const emit = (event, ...args) => {
        if (!events.has(event)) {
            return;
        }
        // Create a copy of the handlers to avoid issues if handlers modify the set
        const handlers = Array.from(events.get(event));
        // Call each handler with the arguments
        for (const handler of handlers) {
            handler(...args);
        }
    };
    const clear = (event) => {
        if (event) {
            events.delete(event);
        }
        else {
            events.clear();
        }
    };
    return { on, once, off, emit, clear };
}
// Create a global event bus instance
const globalEventBus = createEventBus();
// Hook to use the event bus in components
export function useEvent(event, handler, options = {}) {
    return options.once
        ? globalEventBus.once(event, handler)
        : globalEventBus.on(event, handler);
}
export { globalEventBus as eventBus };
export default {
    createEventBus,
    eventBus: globalEventBus,
    useEvent
};