index.js

var newElement = require("./new-element");
var select = require('./select');

module.exports = {
  add: withChildren(add),
  addAfter: withChildren(addAfter),
  addBefore: withChildren(addBefore),
  insert: insert,
  replace: replace,
  remove: remove
};

function add (parent, child, vars) {
  select(parent).appendChild(newElement(child, vars));
}

function addAfter (parent, child/*[, vars], reference */) {
  var ref = select(arguments[arguments.length - 1], parent).nextSibling;
  var vars = arguments.length > 3 ? arguments[2] : undefined;

  if (ref == null) {
    return add(parent, child, vars);
  }

  addBefore(parent, child, vars, ref);
}

function addBefore (parent, child/*[, vars], reference */) {
  var ref = arguments[arguments.length - 1];
  var vars = arguments.length > 3 ? arguments[2] : undefined;
  select(parent).insertBefore(newElement(child, vars), select(ref, parent));
}

function insert (element /*[,vars], parent */) {
  var parent = arguments[arguments.length - 1];
  var vars = arguments.length > 2 ? arguments[1] : undefined;

  add(select(parent), element, vars);
}

function replace (parent, target, repl, vars) {
  select(parent).replaceChild(select(newElement(repl, vars)), select(target, parent));
}

function remove (element, child) {
  var i, all;

  if (arguments.length == 1 && typeof element != 'string') {
    return element.parentNode.removeChild(element);
  }

  all = arguments.length > 1 ? select.all(child, element) : select.all(element);
  i = all.length;

  while (i--) {
    all[i].parentNode.removeChild(all[i]);
  }

}

function withChildren (fn) {
  return function (_, children) {
    if (!Array.isArray(children)) children = [children];

    var i = -1;
    var len = children.length;
    var params = Array.prototype.slice.call(arguments);

    while (++i < len) {
      params[1] = children[i];
      fn.apply(undefined, params);
    }
  };
}