receptor/src/reducers/torrents.js

import {
  UPDATE_RESOURCES,
  RESOURCES_REMOVED
} from '../actions/resources';

export default function torrents(state = {}, action) {
  switch (action.type) {
    case UPDATE_RESOURCES:
      return {
        ...state,
        ...action.resources
          .filter(r => r.type === "torrent")
          .reduce((s, r) => ({
            ...s,
            [r.id]: { ...state[r.id], ...r }
          }), {})
      };
    case RESOURCES_REMOVED:
      return Object.values(state)
        .filter(r => action.ids.indexOf(r.id) === -1)
        .reduce((s, r) => ({ ...s, [r.id]: r }), {});
  }
  return state;
}