fluxx/lib/Store.js

Terse application state management

'use strict';

exports.__esModule = true;
exports.GlobalStore = GlobalStore;
exports.LocalStore = LocalStore;
exports.default = Store;

var storeId = 1;
var stores = exports.stores = {};

function GlobalStore(optionsOrInitialState, registerHandlers) {
  return Store(optionsOrInitialState, registerHandlers, true);
}

function LocalStore(optionsOrInitialState, registerHandlers) {
  return Store(optionsOrInitialState, registerHandlers);
}

function Store(optionsOrInitialState, registerHandlers, isGlobal) {
  var _ref = registerHandlers ? {} : optionsOrInitialState;

  var handlers = _ref.handlers;

  var initialState = registerHandlers ? optionsOrInitialState : optionsOrInitialState.state;
  var onHandlers = {};

  var dispatching = false;
  var callbacks = [];
  var disposeCb = undefined;

  var instance = {
    state: initialState,
    log: Store.log,
    onDispose: function onDispose(cb) {
      disposeCb = cb;return instance;
    }
  };

  instance.id = storeId++;
  stores[instance.id] = instance;

  // on(action, callback) registration style
  if (registerHandlers) {
    var on = function on(action, fn) {
      onHandlers[action] = fn;
    };
    registerHandlers(on);
  }

  instance._handleAction = function (action, payloads) {
    if (dispatching) throw new Error('Cannot dispatch an Action in the middle of another Action\'s dispatch');

    // Bail fast if this store isn't interested.
    var handler = handlers ? handlers[action._id] : onHandlers[action._id];
    if (!handler) return;

    dispatching = true;

    if (instance.log) {
      var payload = payloads.length > 1 ? payloads : payloads[0];
      console.log('%c' + action._name, 'color: #F51DE3', 'dispatched with payload ', payload);
    }

    var previousState = instance.state;

    try {
      instance.state = handlers ? handler.apply(null, [instance.state].concat(payloads)) : handler(instance.state, payloads[0]);
    } finally {
      if (instance.log) {
        var storeKind = isGlobal ? 'global' : 'local';
        console.log('%cNew ' + storeKind + ' state:', 'color: blue', instance.state);
      }

      dispatching = false;
    }

    if (previousState !== instance.state) callbacks.forEach(function (callback) {
      return callback(instance.state);
    });
  };

  instance.subscribe = function (callback) {
    callbacks.push(callback);

    if (instance.log) console.log('%cInitial state:', 'color: green', initialState);

    return function unsubscribe() {
      callbacks = callbacks.filter(function (_callback) {
        return _callback !== callback;
      });

      // Global stores remain active forever, but not local stores
      if (!isGlobal && callbacks.length === 0) {
        delete stores[instance.id];
        if (disposeCb) disposeCb();
      }
    };
  };

  return instance;
}