react-native/Libraries/NavigationExperimental/Reducer/NavigationFindReducer.js

42 lines
1.1 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule NavigationFindReducer
* @flow
*/
'use strict';
/*
* NavigationFindReducer takes an array of reducers, and returns a reducer that
* iterates through all of the reducers and the result of the first reducer
* that modifies the input
*/
import type {
NavigationRoute,
NavigationReducer
} from 'NavigationTypeDefinition';
function NavigationFindReducer(
reducers: Array<NavigationReducer>,
defaultState: NavigationRoute,
): NavigationReducer {
return function(lastState: ?NavigationRoute, action: ?any): NavigationRoute {
for (let i = 0; i < reducers.length; i++) {
let reducer = reducers[i];
let newState = reducer(lastState, action);
if (newState !== lastState) {
return newState || defaultState;
}
}
return lastState || defaultState;
};
}
module.exports = NavigationFindReducer;