index-es5.js

'use strict';

var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; };

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

var extend = require('xtend');
var DuplexStream = require('stream').Duplex;

var ObservableStore = function (_DuplexStream) {
  _inherits(ObservableStore, _DuplexStream);

  function ObservableStore() {
    var initState = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};

    _classCallCheck(this, ObservableStore);

    // dont buffer outgoing updates
    var _this = _possibleConstructorReturn(this, (ObservableStore.__proto__ || Object.getPrototypeOf(ObservableStore)).call(this, {
      // pass values not serializations
      objectMode: true,
      // a writer can end and we are still readable
      allowHalfOpen: true
    }));
    // construct as duplex stream


    _this.resume();
    // set init state
    _this._state = initState;
    return _this;
  }

  // wrapper around internal getState


  _createClass(ObservableStore, [{
    key: 'getState',
    value: function getState() {
      return this._getState();
    }

    // wrapper around internal putState

  }, {
    key: 'putState',
    value: function putState(newState) {
      this._putState(newState);
      this.emit('update', newState);
      this.push(this.getState());
    }
  }, {
    key: 'updateState',
    value: function updateState(partialState) {
      // if non-null object, merge
      if (partialState && (typeof partialState === 'undefined' ? 'undefined' : _typeof(partialState)) === 'object') {
        var state = this.getState();
        var newState = Object.assign({}, state, partialState);
        this.putState(newState);
        // if not object, use new value
      } else {
        this.putState(partialState);
      }
    }

    // subscribe to changes

  }, {
    key: 'subscribe',
    value: function subscribe(handler) {
      this.on('update', handler);
    }

    // unsubscribe to changes

  }, {
    key: 'unsubscribe',
    value: function unsubscribe(handler) {
      this.removeListener('update', handler);
    }

    //
    // private
    //

    // read from persistence

  }, {
    key: '_getState',
    value: function _getState() {
      return this._state;
    }

    // write to persistence

  }, {
    key: '_putState',
    value: function _putState(newState) {
      this._state = newState;
    }

    //
    // stream implementation
    //

    // emit current state on new destination

  }, {
    key: 'pipe',
    value: function pipe(dest, options) {
      var result = DuplexStream.prototype.pipe.call(this, dest, options);
      dest.write(this.getState());
      return result;
    }

    // write from incomming stream to state

  }, {
    key: '_write',
    value: function _write(chunk, encoding, callback) {
      this.putState(chunk);
      callback();
    }

    // noop - outgoing stream is asking us if we have data we arent giving it

  }, {
    key: '_read',
    value: function _read(size) {}
  }]);

  return ObservableStore;
}(DuplexStream);

module.exports = ObservableStore;