Store.js

gistfile1.js

export default class Store {

  listeners = new Set()

  constructor(dispatcher) {
    this.reactions = this.getActionHandlers()
    this.dispatcher = null
    this.dispatchToken = null
    this.actionHandler = this.actionHandler.bind(this)
    this._getOriginalState()
  }

  _getOriginalState() {
    if(__DOM__) {
      const node = document.querySelector(
        `[data-storename=${ this.constructor.displayName }]`
      )
      if(!node) {
        return
      }
      this.state = JSON.parse(node.innerHTML)
      // remove the script after we took the data from it
      node.parentNode.removeChild(node)
    }
  }

  registerDispatcher(dispatcher) {
    this.dispatcher = dispatcher
    this.dispatchToken = this.dispatcher.register(this.actionHandler)
  }

  setState(nextState) {
    this.state = {
      ...this.state,
      ...nextState,
    }
    this.emitChange()
  }

  actionHandler(action){
    if(!this.reactions.hasOwnProperty(action.type)) {
      return
    }
    this.reactions[action.type].call(this, action)
  }

  addChangeListener(func) {
    this.listeners.add(func)
  }

  removeChangeListener(func) {
    this.listeners.delete(func)
  }

  emitChange() {
    this.listeners.forEach((value) => {
      value()
    })
  }
}