redux-tiles/lib/es2015/tiles/reducer.js

Library to create and easily compose redux pieces together in less verbose manner

var __assign = (this && this.__assign) || Object.assign || function(t) {
    for (var s, i = 1, n = arguments.length; i < n; i++) {
        s = arguments[i];
        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
            t[p] = s[p];
    }
    return t;
};
import { forEachRight, get, isFunction, mapValues } from 'lodash';
/**
 * @overview create reducer function from the object
 * @param  {Any} initialState – initial state of this part of the store
 * @param  {Object} handlers – object with keys as action types, and
 * reduce functions to change store as values
 * @return {Function} – function to act as a reducer
 */
export function createReducerFromObject(initialState, handlers) {
    return function reducer(state, action) {
        if (state === void 0) { state = initialState; }
        var handler = handlers[action.type];
        return typeof handler === 'function' ? handler(state, action) : state;
    };
}
/**
 * @overview create reducer from the object, with creating reducing functions
 * @param  {Any} initialState – initial state of this part of the store
 * @param  {Object} handlers – object with keys as action types, and
 * newValues to set at store as values
 * @return {Function} – function to act as a reducer
 */
export function createReducer(initialState, handlers) {
    return createReducerFromObject(initialState, mapValues(handlers, function (value) { return function (state, action) { return reducerCreator({
        state: state,
        action: action,
        newValue: isFunction(value) ? value(state, action) : value
    }); }; }));
}
/**
 * @overview reducer function, which changes the state with new values
 * @param  {Object} action – reducer action object, with type and payload
 * @param  {Object} state – previous redux state in this branch
 * @param  {Any} newValue – new value to set up in state in corresponding path
 * @return {Object} – changed reducer
 */
export function reducerCreator(_a) {
    var action = _a.action, state = _a.state, newValue = _a.newValue;
    var path = action.payload.path;
    var hasNoNestInStore = !path;
    if (hasNoNestInStore) {
        return newValue;
    }
    var result = {};
    var lookupPath;
    // index stays as it was in original array, so the first
    // element in the iteration has `i` of the last element!
    forEachRight(path, function (el, i) {
        var isLastItem = i === path.length - 1;
        var newNestedResult = (_a = {},
            _a[el] = isLastItem ? newValue : result,
            _a);
        lookupPath = path.slice(0, i);
        var oldState = get(state, lookupPath) || {};
        result = __assign({}, oldState, newNestedResult);
        var _a;
    });
    return __assign({}, state, result);
}
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