Function createObj

GUI/codemirror/lib/codemirror.js:7029–7040

(base, props)

  if ([].map) map = function(array, f) { return array.map(f); };

  function createObj(base, props) {
    var inst;
    if (Object.create) {
      inst = Object.create(base);
    } else {
      var ctor = function() {};
      ctor.prototype = base;
      inst = new ctor();
    }
    if (props) copyObj(props, inst);
    return inst;
  };

  function copyObj(obj, target, overwrite) {
    if (!target) target = {};