code: function setVisibility(state, action) {
    let updated = false;
    const updated_layers = [];
  
    for (let i = 0, ii = state.layers.length; i < ii; i++) {
      const layer = state.layers[i];
      if (layer.id === action.layerId) {
        updated_layers.push({
          ...layer,
          layout: {
            ...layer.layout,
            visibility: action.visibility,
          },
        });
        updated = true;
      } else {
        updated_layers.push(layer);
      }
    }
    if (updated) {
      return Object.assign({}, state, {
        layers: updated_layers,
      }, incrementVersion(state.metadata, LAYER_VERSION_KEY));
    }
    // if nothing was updated, return the default state.
    return state;
  }
docs: Change the visibility of a layer given in the action.
  @param {Object} state Current state.
  @param {Object} action Action to handle.
  
  @returns {Object} The new state.