events.js

export default {
  getMousePosition (event) {
    return {
      x: event.pageX - window.scrollX,
      y: event.pageY - window.scrollY
    };
  },

  getTouchPosition (event) {
    return {
      x: event.touches[0].pageX - window.scrollX,
      y: event.touches[0].pageY - window.scrollY
    };
  },

  pauseEvent (event) {
    event.stopPropagation();
    event.preventDefault();
  },

  addEventsToDocument (eventMap) {
    for (const key in eventMap) {
      document.addEventListener(key, eventMap[key], false);
    }
  },

  removeEventsFromDocument (eventMap) {
    for (const key in eventMap) {
      document.removeEventListener(key, eventMap[key], false);
    }
  },

  targetIsDescendant (event, parent) {
    let node = event.target;
    while (node !== null) {
      if (node === parent) return true;
      node = node.parentNode;
    }
    return false;
  },

  addEventListenerOnTransitionEnded (element, fn) {
    const eventName = transitionEventNamesFor(element);
    if (!eventName) return false;
    element.addEventListener(eventName, fn);
    return true;
  },

  removeEventListenerOnTransitionEnded (element) {
    const eventName = transitionEventNamesFor(element);
    if (!eventName) return false;
    element.removeEventListener(eventName);
    return true;
  }
};

const TRANSITIONS = {
  'transition': 'transitionend',
  'OTransition': 'oTransitionEnd',
  'MozTransition': 'transitionend',
  'WebkitTransition': 'webkitTransitionEnd'
};

function transitionEventNamesFor (element) {
  for (const transition in TRANSITIONS) {
    if (element.style[transition] !== undefined) {
      return TRANSITIONS[transition];
    }
  }
}