genji-core/lib/createImmerReducer.js

The core lightweight library for genji, based on redux and redux-saga.

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.combineReducers = combineReducers;
exports.default = createImmerReducer;

var _objectSpread2 = _interopRequireDefault(require("@babel/runtime/helpers/objectSpread"));

var _immer = _interopRequireDefault(require("immer"));

var _invariant = _interopRequireDefault(require("invariant"));

function combineReducers(reducers) {
  return function () {
    var state = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
    var action = arguments.length > 1 ? arguments[1] : undefined;
    var hasChanged = false;
    var nextState = {};

    for (var key in reducers) {
      var prevStateKey = state[key];
      var nextStateKey = reducers[key](prevStateKey, action);
      nextState[key] = nextStateKey;
      hasChanged = hasChanged || nextStateKey !== prevStateKey;
    }

    if (hasChanged == false) {
      return state;
    } else {
      return (0, _objectSpread2.default)({}, state, nextState);
    }
  };
}

function createImmerReducer(reducers) {
  var defaultState = {};
  var mutations = {};

  for (var key in reducers) {
    defaultState[key] = reducers[key].state;

    for (var action in reducers[key].mutations) {
      mutations[action] = reducers[key].mutations[action];
    }
  }

  return function () {
    var state = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
    var action = arguments.length > 1 ? arguments[1] : undefined;
    var addState = {};
    var hasAddState = false;

    for (var _key in defaultState) {
      if (_key in state == false) {
        addState[_key] = defaultState[_key];
        hasAddState = true;
      }
    }

    if (hasAddState) {
      state = (0, _objectSpread2.default)({}, state, addState);
    }

    var type = action.type;
    (0, _invariant.default)(type, 'dispatch: action should be a plain Object with type');
    var handler = mutations[type];

    if (handler) {
      var ret = (0, _immer.default)(state, function (draft) {
        handler(draft, action);
      });
      return ret === undefined ? {} : ret;
    } else {
      return state;
    }
  };
}