@react-navigation/core/lib/module/useNavigationHelpers.js

Core utilities for building navigators

"use strict";

import { CommonActions } from '@react-navigation/routers';
import * as React from 'react';
import { NavigationContext } from "./NavigationContext.js";
import { PrivateValueStore } from "./types.js";
import { UnhandledActionContext } from "./UnhandledActionContext.js";
// This is to make TypeScript compiler happy
// eslint-disable-next-line @typescript-eslint/no-unused-expressions
PrivateValueStore;
/**
 * Navigation object with helper methods to be used by a navigator.
 * This object includes methods for common actions as well as methods the parent screen's navigation object.
 */
export function useNavigationHelpers({
  id: navigatorId,
  onAction,
  getState,
  emitter,
  router,
  stateRef
}) {
  const onUnhandledAction = React.useContext(UnhandledActionContext);
  const parentNavigationHelpers = React.useContext(NavigationContext);
  return React.useMemo(() => {
    const dispatch = op => {
      const action = typeof op === 'function' ? op(getState()) : op;
      const handled = onAction(action);
      if (!handled) {
        onUnhandledAction?.(action);
      }
    };
    const actions = {
      ...router.actionCreators,
      ...CommonActions
    };
    const helpers = Object.keys(actions).reduce((acc, name) => {
      // @ts-expect-error: name is a valid key, but TypeScript is dumb
      acc[name] = (...args) => dispatch(actions[name](...args));
      return acc;
    }, {});
    const navigationHelpers = {
      ...parentNavigationHelpers,
      ...helpers,
      dispatch,
      emit: emitter.emit,
      isFocused: parentNavigationHelpers ? parentNavigationHelpers.isFocused : () => true,
      canGoBack: () => {
        const state = getState();
        return router.getStateForAction(state, CommonActions.goBack(), {
          routeNames: state.routeNames,
          routeParamList: {},
          routeGetIdList: {}
        }) !== null || parentNavigationHelpers?.canGoBack() || false;
      },
      getId: () => navigatorId,
      getParent: id => {
        if (id !== undefined) {
          let current = navigationHelpers;
          while (current && id !== current.getId()) {
            current = current.getParent();
          }
          return current;
        }
        return parentNavigationHelpers;
      },
      getState: () => {
        // FIXME: Workaround for when the state is read during render
        // By this time, we haven't committed the new state yet
        // Without this `useSyncExternalStore` will keep reading the old state
        // This may result in `useNavigationState` or `useIsFocused` returning wrong values
        // Apart from `useSyncExternalStore`, `getState` should never be called during render
        if (stateRef.current != null) {
          return stateRef.current;
        }
        return getState();
      }
    };
    return navigationHelpers;
  }, [router, parentNavigationHelpers, emitter.emit, getState, onAction, onUnhandledAction, navigatorId, stateRef]);
}
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