@samsch/subscribe-store/lib/store.js

A simple subscribable store factory

'use strict';

var createStore = function createStore(initialState) {
  var store = {
    state: initialState || {}
  };
  var listeners = [];

  var replaceState = function replaceState(newState) {
    store.state = newState;
    listeners.forEach(function (callback) {
      return callback(store);
    });
  };

  store.setState = function (updator) {
    var newState = typeof updator === 'function' ? updator(store.state) : updator;
    replaceState(newState);
  };
  store.updateState = function (updator) {
    var newState = typeof updator === 'function' ? updator(store.state) : updator;
    replaceState(Object.assign({}, store.state, newState));
  };
  store.subscribe = function (callback) {
    listeners.push(callback);
    return function () {
      return store.unsubscribe(callback);
    };
  };
  store.unsubscribe = function (callback) {
    var index = listeners.indexOf(callback);
    if (index < 0) {
      return false;
    }
    listeners.splice(index, 1);
    return store;
  };
  return store;
};

module.exports = createStore;