function isObj(obj) {
  return (obj && typeof obj === 'object' && obj !== null) ? true : false;
}

function createEl(element = 'div') {
  return document.createElement(element);
}

function elem(selector, parent = document){
  let elem = parent.querySelector(selector);
  return elem != false ? elem : false;
}

function elems(selector, parent = document) {
  let elems = parent.querySelectorAll(selector);
  return elems.length ? elems : false;
}

function pushClass(el, targetClass) {
  if (isObj(el) && targetClass) {
    elClass = el.classList;
    elClass.contains(targetClass) ? false : elClass.add(targetClass);
  }
}

function deleteClass(el, targetClass) {
  if (isObj(el) && targetClass) {
    elClass = el.classList;
    elClass.contains(targetClass) ? elClass.remove(targetClass) : false;
  }
}

function modifyClass(el, targetClass) {
  if (isObj(el) && targetClass) {
    elClass = el.classList;
    elClass.contains(targetClass) ? elClass.remove(targetClass) : elClass.add(targetClass);
  }
}

function containsClass(el, targetClass) {
  if (isObj(el) && targetClass && el !== document ) {
    return el.classList.contains(targetClass) ? true : false;
  }
}

function isChild(node, parentClass) {
  let objectsAreValid = isObj(node) && parentClass && typeof parentClass == 'string';
  return (objectsAreValid && node.closest(parentClass)) ? true : false;
}

function getSiblings(el) {
  return Array.prototype.filter.call(el.parentNode.children, function(child){
    return child !== el;
  });
}

function markActive(el, activeClass = active) {
  const siblings = getSiblings(el);
  pushClass(el, activeClass);
  if(siblings.length) {
    siblings.forEach(element => deleteClass(element, activeClass));
  }
}

function elemAttribute(elem, attr, value = null) {
  if (value) {
    elem.setAttribute(attr, value);
  } else {
    value = elem.getAttribute(attr);
    return value ? value : false;
  }
}

function deleteChars(str, subs) {
  let newStr = str;
  if (Array.isArray(subs)) {
    for (let i = 0; i < subs.length; i++) {
      newStr = newStr.replace(subs[i], '');
    }
  } else {
    newStr = newStr.replace(subs, '');
  }
  return newStr;
}

function isBlank(str) {
  return (!str || str.trim().length === 0);
}

function isMatch(element, selectors) {
  if(isObj(element)) {
    if(selectors.isArray) {
      let matching = selectors.map(function(selector){
        return element.matches(selector)
      })
      return matching.includes(true);
    }
    return element.matches(selectors)
  }
}

function exactMatch(target, criteria) {
  const isTarget = target.matches(criteria);
  const isWithinTarget = target.closest(criteria);
  return isTarget ? isTarget : isWithinTarget;;
}

const copyToClipboard = str => {
  let copy, selection, selected;
  copy = createEl('textarea');
  copy.value = str;
  copy.setAttribute('readonly', '');
  copy.style.position = 'absolute';
  copy.style.left = '-9999px';
  selection = document.getSelection();
  doc.appendChild(copy);
  // check if there is any selected content
  selected = selection.rangeCount > 0 ? selection.getRangeAt(0) : false;
  copy.select();
  document.execCommand('copy');
  doc.removeChild(copy);
  if (selected) { // if a selection existed before copying
    selection.removeAllRanges(); // unselect existing selection
    selection.addRange(selected); // restore the original selection
  }
}

function convertToUnderScoreCase(str) {
  let char, newChar, newStr;
  newStr = '';
  if (typeof str == 'string') {
    for (let x = 0; x < str.length; x++) {
      char = str.charAt(x);
      if (char.match(/^[A-Z]*$/)) {
        char = char.toLowerCase();
        newChar = `_${char}`
        newStr += newChar;
      } else {
        newStr += char;
      }
    }
    return newStr;
  }
}

function elementInViewport(el) {
  var top = el.offsetTop;
  var left = el.offsetLeft;
  var width = el.offsetWidth;
  var height = el.offsetHeight;

  while(el.offsetParent) {
    el = el.offsetParent;
    top += el.offsetTop;
    left += el.offsetLeft;
  }

  return (
    top < (window.pageYOffset + window.innerHeight) &&
    left < (window.pageXOffset + window.innerWidth) &&
    (top + height) > window.pageYOffset &&
    (left + width) > window.pageXOffset
  );
}