mirador/src/state/reducers/layers.js

An open-source, web-based 'multi-up' viewer that supports zoom-pan-rotate functionality, ability to display/compare simple images, and images with annotations.

import omit from 'lodash/omit';
import deepmerge from 'deepmerge';
import ActionTypes from '../actions/action-types';

/**
 * configReducer - does a deep merge of the config
 */
export const layersReducer = (state = {}, action) => {
  switch (action.type) {
    case ActionTypes.UPDATE_LAYERS:
      return {
        ...state,
        [action.windowId]: {
          ...state[action.windowId],
          [action.canvasId]: deepmerge(
            (state[action.windowId] || {})[action.canvasId] || {},
            action.payload,
          ),
        },
      };
    case ActionTypes.REMOVE_WINDOW:
      return omit(state, [action.windowId]);
    default:
      return state;
  }
};