react-native/packages/rn-tester/js/utils/RNTesterNavigationReducer.js

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 * @flow
 */

import type {
  RNTesterNavigationState,
  ComponentList,
} from '../types/RNTesterTypes';

export const RNTesterNavigationActionsType = {
  NAVBAR_PRESS: 'NAVBAR_PRESS',
  BACK_BUTTON_PRESS: 'BACK_BUTTON_PRESS',
  MODULE_CARD_PRESS: 'MODULE_CARD_PRESS',
  EXAMPLE_CARD_PRESS: 'EXAMPLE_CARD_PRESS',
};

const getUpdatedRecentlyUsed = ({
  exampleType,
  key,
  recentlyUsed,
}: {
  exampleType: 'apis' | 'components' | null,
  key: string | null,
  recentlyUsed: ComponentList,
}) => {
  const updatedRecentlyUsed = recentlyUsed
    ? {...recentlyUsed}
    : // $FlowFixMe[missing-empty-array-annot]
      {components: [], apis: []};

  if (!exampleType || !key) {
    return updatedRecentlyUsed;
  }

  let existingKeys = updatedRecentlyUsed[exampleType];

  if (existingKeys.includes(key)) {
    existingKeys = existingKeys.filter(k => k !== key);
  }
  // $FlowFixMe[incompatible-call]
  existingKeys.unshift(key);

  updatedRecentlyUsed[exampleType] = existingKeys.slice(0, 5);

  return updatedRecentlyUsed;
};

export const RNTesterNavigationReducer = (
  state: RNTesterNavigationState,
  action: {type: $Keys<typeof RNTesterNavigationActionsType>, data?: any},
): RNTesterNavigationState => {
  const {
    data: {key = null, title = null, exampleType = null, screen = null} = {},
  } = action;

  switch (action.type) {
    case RNTesterNavigationActionsType.NAVBAR_PRESS:
      return {
        ...state,
        activeModuleKey: null,
        activeModuleTitle: null,
        activeModuleExampleKey: null,
        screen,
      };

    case RNTesterNavigationActionsType.MODULE_CARD_PRESS:
      return {
        ...state,
        activeModuleKey: key,
        activeModuleTitle: title,
        activeModuleExampleKey: null,
        // $FlowFixMe[incompatible-return]
        recentlyUsed: getUpdatedRecentlyUsed({
          exampleType: exampleType,
          key: key,
          recentlyUsed: state.recentlyUsed,
        }),
      };

    case RNTesterNavigationActionsType.EXAMPLE_CARD_PRESS:
      return {
        ...state,
        activeModuleExampleKey: key,
      };

    case RNTesterNavigationActionsType.BACK_BUTTON_PRESS:
      // Go back to module or list
      return {
        ...state,
        activeModuleExampleKey: null,
        activeModuleKey:
          state.activeModuleExampleKey != null ? state.activeModuleKey : null,
        activeModuleTitle:
          state.activeModuleExampleKey != null ? state.activeModuleTitle : null,
      };

    default:
      throw new Error(`Invalid action type ${action.type}`);
  }
};