143 lines
6.1 KiB
JavaScript
143 lines
6.1 KiB
JavaScript
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'use strict';
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exports.__esModule = true;
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exports['default'] = combineReducers;
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var _createStore = require('./createStore');
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var _isPlainObject = require('lodash/isPlainObject');
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var _isPlainObject2 = _interopRequireDefault(_isPlainObject);
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var _warning = require('./utils/warning');
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var _warning2 = _interopRequireDefault(_warning);
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }
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function getUndefinedStateErrorMessage(key, action) {
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var actionType = action && action.type;
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var actionName = actionType && '"' + actionType.toString() + '"' || 'an action';
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return 'Given action ' + actionName + ', reducer "' + key + '" returned undefined. ' + 'To ignore an action, you must explicitly return the previous state. ' + 'If you want this reducer to hold no value, you can return null instead of undefined.';
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}
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function getUnexpectedStateShapeWarningMessage(inputState, reducers, action, unexpectedKeyCache) {
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var reducerKeys = Object.keys(reducers);
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var argumentName = action && action.type === _createStore.ActionTypes.INIT ? 'preloadedState argument passed to createStore' : 'previous state received by the reducer';
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if (reducerKeys.length === 0) {
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return 'Store does not have a valid reducer. Make sure the argument passed ' + 'to combineReducers is an object whose values are reducers.';
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}
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if (!(0, _isPlainObject2['default'])(inputState)) {
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return 'The ' + argumentName + ' has unexpected type of "' + {}.toString.call(inputState).match(/\s([a-z|A-Z]+)/)[1] + '". Expected argument to be an object with the following ' + ('keys: "' + reducerKeys.join('", "') + '"');
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}
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var unexpectedKeys = Object.keys(inputState).filter(function (key) {
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return !reducers.hasOwnProperty(key) && !unexpectedKeyCache[key];
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});
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unexpectedKeys.forEach(function (key) {
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unexpectedKeyCache[key] = true;
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});
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if (unexpectedKeys.length > 0) {
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return 'Unexpected ' + (unexpectedKeys.length > 1 ? 'keys' : 'key') + ' ' + ('"' + unexpectedKeys.join('", "') + '" found in ' + argumentName + '. ') + 'Expected to find one of the known reducer keys instead: ' + ('"' + reducerKeys.join('", "') + '". Unexpected keys will be ignored.');
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}
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}
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function assertReducerShape(reducers) {
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Object.keys(reducers).forEach(function (key) {
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var reducer = reducers[key];
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var initialState = reducer(undefined, { type: _createStore.ActionTypes.INIT });
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if (typeof initialState === 'undefined') {
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throw new Error('Reducer "' + key + '" returned undefined during initialization. ' + 'If the state passed to the reducer is undefined, you must ' + 'explicitly return the initial state. The initial state may ' + 'not be undefined. If you don\'t want to set a value for this reducer, ' + 'you can use null instead of undefined.');
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}
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var type = '@@redux/PROBE_UNKNOWN_ACTION_' + Math.random().toString(36).substring(7).split('').join('.');
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if (typeof reducer(undefined, { type: type }) === 'undefined') {
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throw new Error('Reducer "' + key + '" returned undefined when probed with a random type. ' + ('Don\'t try to handle ' + _createStore.ActionTypes.INIT + ' or other actions in "redux/*" ') + 'namespace. They are considered private. Instead, you must return the ' + 'current state for any unknown actions, unless it is undefined, ' + 'in which case you must return the initial state, regardless of the ' + 'action type. The initial state may not be undefined, but can be null.');
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}
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});
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}
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/**
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* Turns an object whose values are different reducer functions, into a single
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* reducer function. It will call every child reducer, and gather their results
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* into a single state object, whose keys correspond to the keys of the passed
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* reducer functions.
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*
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* @param {Object} reducers An object whose values correspond to different
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* reducer functions that need to be combined into one. One handy way to obtain
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* it is to use ES6 `import * as reducers` syntax. The reducers may never return
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* undefined for any action. Instead, they should return their initial state
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* if the state passed to them was undefined, and the current state for any
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* unrecognized action.
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*
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* @returns {Function} A reducer function that invokes every reducer inside the
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* passed object, and builds a state object with the same shape.
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*/
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function combineReducers(reducers) {
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var reducerKeys = Object.keys(reducers);
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var finalReducers = {};
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for (var i = 0; i < reducerKeys.length; i++) {
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var key = reducerKeys[i];
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if (process.env.NODE_ENV !== 'production') {
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if (typeof reducers[key] === 'undefined') {
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(0, _warning2['default'])('No reducer provided for key "' + key + '"');
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}
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}
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if (typeof reducers[key] === 'function') {
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finalReducers[key] = reducers[key];
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}
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}
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var finalReducerKeys = Object.keys(finalReducers);
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var unexpectedKeyCache = void 0;
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if (process.env.NODE_ENV !== 'production') {
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unexpectedKeyCache = {};
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}
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var shapeAssertionError = void 0;
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try {
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assertReducerShape(finalReducers);
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} catch (e) {
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shapeAssertionError = e;
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}
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return function combination() {
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var state = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
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var action = arguments[1];
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if (shapeAssertionError) {
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throw shapeAssertionError;
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}
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if (process.env.NODE_ENV !== 'production') {
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var warningMessage = getUnexpectedStateShapeWarningMessage(state, finalReducers, action, unexpectedKeyCache);
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if (warningMessage) {
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(0, _warning2['default'])(warningMessage);
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}
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}
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var hasChanged = false;
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var nextState = {};
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for (var _i = 0; _i < finalReducerKeys.length; _i++) {
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var _key = finalReducerKeys[_i];
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var reducer = finalReducers[_key];
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var previousStateForKey = state[_key];
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var nextStateForKey = reducer(previousStateForKey, action);
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if (typeof nextStateForKey === 'undefined') {
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var errorMessage = getUndefinedStateErrorMessage(_key, action);
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throw new Error(errorMessage);
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}
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nextState[_key] = nextStateForKey;
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hasChanged = hasChanged || nextStateForKey !== previousStateForKey;
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}
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return hasChanged ? nextState : state;
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};
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}
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