@mui/base/node/utils/useMessageBus.js

MUI Base is a library of headless ('unstyled') React components and low-level hooks. You gain complete control over your app's CSS and accessibility features.

"use strict";
'use client';

var _interopRequireWildcard = require("@babel/runtime/helpers/interopRequireWildcard").default;
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createMessageBus = createMessageBus;
exports.useMessageBus = useMessageBus;
var React = _interopRequireWildcard(require("react"));
function createMessageBus() {
  const listeners = new Map();
  function subscribe(topic, callback) {
    let topicListeners = listeners.get(topic);
    if (!topicListeners) {
      topicListeners = new Set([callback]);
      listeners.set(topic, topicListeners);
    } else {
      topicListeners.add(callback);
    }
    return () => {
      topicListeners.delete(callback);
      if (topicListeners.size === 0) {
        listeners.delete(topic);
      }
    };
  }
  function publish(topic, ...args) {
    const topicListeners = listeners.get(topic);
    if (topicListeners) {
      topicListeners.forEach(callback => callback(...args));
    }
  }
  return {
    subscribe,
    publish
  };
}

/**
 * @ignore - internal hook.
 */
function useMessageBus() {
  const bus = React.useRef(undefined);
  if (!bus.current) {
    bus.current = createMessageBus();
  }
  return bus.current;
}