src/reducers/map.js
function updateMetadata(state, action) {
  return Object.assign({}, state, {
    metadata: Object.assign({}, state.metadata, action.metadata),
  });
}
function updateMetadata(state, action) {
  return Object.assign({}, state, {
    metadata: Object.assign({}, state.metadata, action.metadata),
  });
}
Update the map's metadata.
@param {Object} state The redux state.
@param {Object} action The selected action object.

@returns {Object} The new state object.