redux-live-undo/lib/NextState.js

A high-order reducer that enables generic undo/redo functionality without giving up live updates

'use strict';

Object.defineProperty(exports, "__esModule", {
	value: true
});

var _lodash = require('lodash.isequal');

var _lodash2 = _interopRequireDefault(_lodash);

var _lodash3 = require('lodash.last');

var _lodash4 = _interopRequireDefault(_lodash3);

var _lodash5 = require('lodash.mapvalues');

var _lodash6 = _interopRequireDefault(_lodash5);

var _lodash7 = require('lodash.some');

var _lodash8 = _interopRequireDefault(_lodash7);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var DEFAULT_CHANGE_DETECTOR = function DEFAULT_CHANGE_DETECTOR(lastState, nextState) {
	return !(0, _lodash2.default)(lastState, nextState);
};

var getNextState = function getNextState(reducers, state, action) {
	var subValues = (0, _lodash6.default)(reducers, function (r, k) {
		var nextState = r(state.present[k], action);
		var changeDetector = r.changeDetector || DEFAULT_CHANGE_DETECTOR;

		var lastState = (0, _lodash4.default)(state.past) ? (0, _lodash4.default)(state.past)[k] : undefined;
		var changed = changeDetector(lastState, nextState);

		return {
			changed: changed,
			nextState: nextState
		};
	});

	var nextState = (0, _lodash6.default)(subValues, 'nextState');
	var anyChanged = (0, _lodash8.default)((0, _lodash6.default)(subValues, 'changed'));

	return { nextState: nextState, anyChanged: anyChanged };
};

exports.default = getNextState;