masto-fe-archos/app/javascript/mastodon/reducers/domain_lists.js

import { Map as ImmutableMap, OrderedSet as ImmutableOrderedSet } from "immutable";

import {
  DOMAIN_BLOCKS_FETCH_SUCCESS,
  DOMAIN_BLOCKS_EXPAND_SUCCESS,
  DOMAIN_UNBLOCK_SUCCESS,
} from "../actions/domain_blocks";

const initialState = ImmutableMap({
  blocks: ImmutableMap({
    items: ImmutableOrderedSet(),
  }),
});

export default function domainLists(state = initialState, action) {
  switch(action.type) {
    case DOMAIN_BLOCKS_FETCH_SUCCESS:
      return state.setIn(["blocks", "items"], ImmutableOrderedSet(action.domains)).setIn(["blocks", "next"], action.next);
    case DOMAIN_BLOCKS_EXPAND_SUCCESS:
      return state.updateIn(["blocks", "items"], set => set.union(action.domains)).setIn(["blocks", "next"], action.next);
    case DOMAIN_UNBLOCK_SUCCESS:
      return state.updateIn(["blocks", "items"], set => set.delete(action.domain));
    default:
      return state;
  }
}