hometown/app/javascript/mastodon/actions/streaming.js

// @ts-check

import { connectStream } from '../stream';
import {
  updateTimeline,
  deleteFromTimelines,
  expandHomeTimeline,
  connectTimeline,
  disconnectTimeline,
  fillHomeTimelineGaps,
  fillPublicTimelineGaps,
  fillCommunityTimelineGaps,
  fillListTimelineGaps,
} from './timelines';
import { updateNotifications, expandNotifications } from './notifications';
import { updateConversations } from './conversations';
import { updateStatus } from './statuses';
import {
  fetchAnnouncements,
  updateAnnouncements,
  updateReaction as updateAnnouncementsReaction,
  deleteAnnouncement,
} from './announcements';
import { getLocale } from '../locales';

const { messages } = getLocale();

/**
 * @param {number} max
 * @return {number}
 */
const randomUpTo = max =>
  Math.floor(Math.random() * Math.floor(max));

/**
 * @param {string} timelineId
 * @param {string} channelName
 * @param {Object.<string, string>} params
 * @param {Object} options
 * @param {function(Function, Function): void} [options.fallback]
 * @param {function(): void} [options.fillGaps]
 * @param {function(object): boolean} [options.accept]
 * @return {function(): void}
 */
export const connectTimelineStream = (timelineId, channelName, params = {}, options = {}) =>
  connectStream(channelName, params, (dispatch, getState) => {
    const locale = getState().getIn(['meta', 'locale']);

    // @ts-expect-error
    let pollingId;

    /**
     * @param {function(Function, Function): void} fallback
     */
    const useFallback = fallback => {
      fallback(dispatch, () => {
        pollingId = setTimeout(() => useFallback(fallback), 20000 + randomUpTo(20000));
      });
    };

    return {
      onConnect() {
        dispatch(connectTimeline(timelineId));

        // @ts-expect-error
        if (pollingId) {
          // @ts-ignore
          clearTimeout(pollingId); pollingId = null;
        }

        if (options.fillGaps) {
          dispatch(options.fillGaps());
        }
      },

      onDisconnect() {
        dispatch(disconnectTimeline(timelineId));

        if (options.fallback) {
          // @ts-expect-error
          pollingId = setTimeout(() => useFallback(options.fallback), randomUpTo(40000));
        }
      },

      onReceive(data) {
        switch (data.event) {
        case 'update':
          // @ts-expect-error
          dispatch(updateTimeline(timelineId, JSON.parse(data.payload), options.accept));
          break;
        case 'status.update':
          // @ts-expect-error
          dispatch(updateStatus(JSON.parse(data.payload)));
          break;
        case 'delete':
          dispatch(deleteFromTimelines(data.payload));
          break;
        case 'notification':
          // @ts-expect-error
          dispatch(updateNotifications(JSON.parse(data.payload), messages, locale));
          break;
        case 'conversation':
          // @ts-expect-error
          dispatch(updateConversations(JSON.parse(data.payload)));
          break;
        case 'announcement':
          // @ts-expect-error
          dispatch(updateAnnouncements(JSON.parse(data.payload)));
          break;
        case 'announcement.reaction':
          // @ts-expect-error
          dispatch(updateAnnouncementsReaction(JSON.parse(data.payload)));
          break;
        case 'announcement.delete':
          dispatch(deleteAnnouncement(data.payload));
          break;
        }
      },
    };
  });

/**
 * @param {Function} dispatch
 * @param {function(): void} done
 */
const refreshHomeTimelineAndNotification = (dispatch, done) => {
  // @ts-expect-error
  dispatch(expandHomeTimeline({}, () =>
    // @ts-expect-error
    dispatch(expandNotifications({}, () =>
      dispatch(fetchAnnouncements(done))))));
};

/**
 * @return {function(): void}
 */
export const connectUserStream = () =>
  // @ts-expect-error
  connectTimelineStream('home', 'user', {}, { fallback: refreshHomeTimelineAndNotification, fillGaps: fillHomeTimelineGaps });

/**
 * @param {Object} options
 * @param {boolean} [options.onlyMedia]
 * @return {function(): void}
 */
export const connectCommunityStream = ({ onlyMedia } = {}) =>
  connectTimelineStream(`community${onlyMedia ? ':media' : ''}`, `public:local${onlyMedia ? ':media' : ''}`, {}, { fillGaps: () => (fillCommunityTimelineGaps({ onlyMedia })) });

/**
 * @param {Object} options
 * @param {boolean} [options.onlyMedia]
 * @param {boolean} [options.onlyRemote]
 * @return {function(): void}
 */
export const connectPublicStream = ({ onlyMedia, onlyRemote } = {}) =>
  connectTimelineStream(`public${onlyRemote ? ':remote' : ''}${onlyMedia ? ':media' : ''}`, `public${onlyRemote ? ':remote' : ''}${onlyMedia ? ':media' : ''}`, {}, { fillGaps: () => fillPublicTimelineGaps({ onlyMedia, onlyRemote }) });

/**
 * @param {string} columnId
 * @param {string} tagName
 * @param {boolean} onlyLocal
 * @param {function(object): boolean} accept
 * @return {function(): void}
 */
export const connectHashtagStream = (columnId, tagName, onlyLocal, accept) =>
  connectTimelineStream(`hashtag:${columnId}${onlyLocal ? ':local' : ''}`, `hashtag${onlyLocal ? ':local' : ''}`, { tag: tagName }, { accept });

/**
 * @return {function(): void}
 */
export const connectDirectStream = () =>
  connectTimelineStream('direct', 'direct');

/**
 * @param {string} listId
 * @return {function(): void}
 */
export const connectListStream = listId =>
  connectTimelineStream(`list:${listId}`, 'list', { list: listId }, { fillGaps: () => fillListTimelineGaps(listId) });