typesafe-actions-reducer-builder/lib/createReducerBuilder.js

Reducer builder for typesafe-actions, including immer for reducer's output

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
var immer_1 = __importDefault(require("immer"));
// Implementation
/**
 * Create a reducer builder, starting from its state.
 * It supports multiple actions (from typesafe-actions) with multiple reducers.
 * When the reducers are all set, just call build() to create the root reducer.
 *
 * It uses immer, which will produce an Immutable<TState> object as the result
 * of the reducer. The developer should edit the state in the reducer, instead
 * of creating a new one: immer will take care of creating a new object.
 *
 * The builder will provide type hints along all the build structure, lowering
 * the possibility of creating bugs.
 *
 * @param initialState the reducer's initial state
 */
function createReducerBuilder(initialState) {
    var reducersMap = {};
    var rootReducer = function (state, action) {
        if (state === void 0) { state = initialState; }
        var reducers = reducersMap[action.type] || [];
        reducers.forEach(function (reducer) {
            state = reducer(state, action);
        });
        return state;
    };
    var build = function () { return immer_1.default(rootReducer); };
    var reducerBuilder = {};
    var handlerBuilder = function (actionCreatorBuilder) {
        var handler = {};
        // Get the action's type
        var type = actionCreatorBuilder(null, null).type;
        var addReducer = function (reducer) {
            if (!(type in reducersMap)) {
                reducersMap[type] = [];
            }
            reducersMap[type].push(reducer);
            return handler;
        };
        handler.reducer = addReducer;
        handler.handle = handlerBuilder;
        handler.build = build;
        return handler;
    };
    reducerBuilder.build = build;
    reducerBuilder.handle = handlerBuilder;
    return reducerBuilder;
}
exports.default = createReducerBuilder;
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