67 lines
1.8 KiB
JavaScript
67 lines
1.8 KiB
JavaScript
/* @flow */
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import { combineReducers } from 'redux';
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import type { Reducer } from 'redux';
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/**
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* The type of the dictionary/map which associates a reducer (function) with the
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* name of he Redux state property managed by the reducer.
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*/
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declare type NameReducerMap<S, A> = { [name: string]: Reducer<S, A> };
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/**
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* A registry for Redux reducers, allowing features to register themselves
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* without needing to create additional inter-feature dependencies.
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*/
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class ReducerRegistry {
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_elements: NameReducerMap<*, *>;
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/**
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* Creates a ReducerRegistry instance.
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*/
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constructor() {
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/**
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* The set of registered reducers, keyed based on the field each reducer
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* will manage.
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*
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* @private
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* @type {NameReducerMap}
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*/
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this._elements = {};
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}
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/**
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* Combines all registered reducers into a single reducing function.
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*
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* @param {Object} [additional={}] - Any additional reducers that need to be
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* included (such as reducers from third-party modules).
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* @returns {Function}
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*/
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combineReducers(additional: NameReducerMap<*, *> = {}) {
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// $FlowExpectedError
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return combineReducers({
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...this._elements,
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...additional
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});
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}
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/**
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* Adds a reducer to the registry.
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*
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* The method is to be invoked only before {@link #combineReducers()}.
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*
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* @param {string} name - The field in the state object that will be managed
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* by the provided reducer.
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* @param {Reducer} reducer - A Redux reducer.
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* @returns {void}
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*/
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register(name: string, reducer: Reducer<*, *>) {
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this._elements[name] = reducer;
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}
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}
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/**
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* The public singleton instance of the ReducerRegistry class.
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*/
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export default new ReducerRegistry();
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