util.js

/**
 * util.js module.
 * @module util
 */
'use strict';

/**
 * check if variable is an element
 * @param  {*} potential element
 * @return {Boolean} return true if is an element
 */
function isElement(element) {
  try {
    // eslint-disable-next-line no-undef
    return element instanceof Element;
  } catch (error) {
    return !!(element && element.nodeType === 1);
  }
}

/**
 * createElement shortcut
 * @param  {String} tag
 * @return {Element} element
 */
function el(element) {
  var classes = [];
  var tag = element;
  var el;

  if (isElement(element)) {
    return element;
  }

  classes = element.split('.');
  if (classes.length > 1) {
    tag = classes[0];
  }
  el = document.createElement(tag);
  addClass(el, classes.slice(1));

  return el;
}

/**
 * createDocumentFragment shortcut
 * @return {DocumentFragment}
 */
function frag() {
  return document.createDocumentFragment();
}

/**
 * createTextNode shortcut
 * @return {TextNode}
 */
function text(text) {
  return document.createTextNode(text);
}

/**
 * remove element
 * @param  {Element} element to remove
 * @return {Element} removed element
 */
function remove(element) {
  if ('remove' in element) {
    element.remove();
  } else {
    element.parentNode.removeChild(element);
  }

  return element;
}

/**
 * Find first element that tests true, starting with the element itself
 * and traversing up through its ancestors
 * @param  {Element} element
 * @param  {Function} test fn - return true when element located
 * @return {Element}
 */
function closest(element, test) {
  var el = element;

  while (el) {
    if (test(el)) {
      return el;
    }
    el = el.parentNode;
  }

  return null;
}

/**
 * Add one or more classnames to an element
 * @param {Element} element
 * @param {Array.<string>|String} array of classnames or string with
 * classnames separated by whitespace
 * @return {Element}
 */
function addClass(element, className) {
  var classNames = className;

  function _addClass(el, cn) {
    if (!el.className) {
      el.className = cn;
    } else if (!hasClass(el, cn)) {
      if (el.classList) {
        el.classList.add(cn);
      } else {
        el.className += ' ' + cn;
      }
    }
  }

  if (!Array.isArray(className)) {
    classNames = className.trim().split(/\s+/);
  }
  classNames.forEach(_addClass.bind(null, element));

  return element;
}

/**
 * Remove a class from an element
 * @param  {Element} element
 * @param  {Array.<string>|String} array of classnames or string with
 * @return {Element}
 */
function removeClass(element, className) {
  var classNames = className;

  function _removeClass(el, cn) {
    var classRegex;
    if (el.classList) {
      el.classList.remove(cn);
    } else {
      classRegex = new RegExp('(?:^|\\s)' + cn + '(?!\\S)', 'g');
      el.className = el.className.replace(classRegex, '').trim();
    }
  }

  if (!Array.isArray(className)) {
    classNames = className.trim().split(/\s+/);
  }
  classNames.forEach(_removeClass.bind(null, element));

  return element;
}

/**
 * Check if element has a class
 * @param  {Element}  element
 * @param  {String}  className
 * @return {boolean}
 */
function hasClass(element, className) {
  if (!element || !('className' in element)) {
    return false;
  }

  return element.className.split(/\s+/).indexOf(className) !== -1;
}

/**
 * Return all next siblings
 * @param  {Element} element
 * @return {Array.<element>}
 */
function nextSiblings(element) {
  var next = element.nextSibling;
  var siblings = [];

  while (next) {
    siblings.push(next);
    next = next.nextSibling;
  }

  return siblings;
}

/**
 * Return all prev siblings
 * @param  {Element} element
 * @return {Array.<element>}
 */
function previousSiblings(element) {
  var prev = element.previousSibling;
  var siblings = [];

  while (prev) {
    siblings.push(prev);
    prev = prev.previousSibling;
  }

  return siblings;
}

/**
 * Stop event propagation
 * @param  {Event} event
 * @return {Event}
 */
function stop(event) {
  event.stopPropagation();
  event.preventDefault();

  return event;
}

/**
 * Returns first element in parent that matches selector
 * @param  {Element} parent
 * @param  {String} selector
 * @return {Element | null}
 */
function first(parent, selector) {
  return parent.querySelector(selector);
}

function append(parent, _children) {
  var _frag = frag();
  var children = Array.isArray(_children) ? _children : [_children];

  children.forEach(_frag.appendChild.bind(_frag));
  parent.appendChild(_frag);

  return parent;
}

module.exports = {
  el: el,
  frag: frag,
  text: text,
  closest: closest,
  addClass: addClass,
  removeClass: removeClass,
  hasClass: hasClass,
  nextSiblings: nextSiblings,
  previousSiblings: previousSiblings,
  remove: remove,
  stop: stop,
  first: first,
  append: append
};