elliptical-observe-inline/lib-node/store.js

Dynamic sideways Data Loading for Elliptical

'use strict';

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

var _lodash = require('lodash');

var _lodash2 = _interopRequireDefault(_lodash);

var _zenObservable = require('zen-observable');

var _zenObservable2 = _interopRequireDefault(_zenObservable);

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

function createStore() {
  const items = [];
  let observer;
  const data = new _zenObservable2.default(newObserver => {
    observer = newObserver;
  });

  function fetchAndSubscribe(element, item) {
    const fetched = element.type.fetch(element);

    const subscription = fetched.subscribe({
      next(value) {
        item.value = value;

        if (observer) {
          observer.next({ element, value });
        }
      }
    });
    if (item.subscription) {
      item.subscription.unsubscribe();
    }
    item.subscription = subscription;
  }

  function register(element) {
    const existing = _lodash2.default.find(items, item => _lodash2.default.isEqual(element, item.element));

    if (existing) {
      const currentValue = existing.value;

      return currentValue;
    } else {
      const newItem = { element, dirty: false };
      items.push(newItem);

      fetchAndSubscribe(element, newItem);

      return newItem.value;
    }
  }

  function remove(item) {
    const index = items.indexOf(item);
    const removed = items.splice(index, 1);
    removed[0].subscription.unsubscribe();
  }

  return { data, register, items, remove };
}