Generate javascript code that will create a clone of a given javascript object

cloneobjectstring.js

    function buildValMap(obj, m) {
      if (typeof obj !== 'object' || obj === null) {
        return '';
      }
      if (obj === Object.prototype || obj === Array.prototype) {
        return '';
      }
      if (m.has(obj)) {
        return '';
      }
      var num = m.size;
      m.set(obj, num);


      if (obj instanceof Uint8Array) {
        return 'var v' + num + '=new Uint8Array([' + obj.toString() + ']);\n';
      }

      var str = '';
      str += buildValMap(Object.getPrototypeOf(obj), m);

      var keys = Object.getOwnPropertyNames(obj);
      for (var k in keys) {
        var key = keys[k];
        var val = obj[key];
        str += buildValMap(val, m);
      }

      if (Array.isArray(obj)) {
        str += 'var v' + num + '=[];\n';
      } else {
        if (Object.getPrototypeOf(obj) !== Object.prototype) {
          var prototypeRef = 'v' + m.get(Object.getPrototypeOf(obj));
          str += 'var v' + num + '=Object.create(' + prototypeRef + ');\n';
        } else {
          str += 'var v' + num + '=Object.create(Object.prototype);\n';
        }
      }
      return str;
    }

    function stringifyPrimitive(v) {
      if (typeof v === 'string') {
        return '\'' + v + '\'';
      } else {
        return '' + v;
      }
    }

    function buildObjectInternal(obj, m) {
      if (obj === Object.prototype || obj === Array.prototype) {
        return '';
      }
      if (obj === Uint8Array) {
        return '';
      }

      if (Array.isArray(obj)) {
        var arrStr = 'v' + m.get(obj) + '=[';
        var isFirst = true;
        obj.forEach(function(val) {
          if (isFirst) {
            isFirst = false;
          } else {
            arrStr += ',';
          }
          if (typeof val === 'object' && val !== null) {
            arrStr += 'v'+m.get(val);
          } else {
            arrStr += stringifyPrimitive(val);
          }
        });
        arrStr += '];\n';
        return arrStr;
      }

      var str = '';
      var keys = Object.getOwnPropertyNames(obj);
      for (var k in keys) {
        var key = keys[k];
        var desc = Object.getOwnPropertyDescriptor(obj, key);
        str += 'Object.defineProperty(v' + m.get(obj) + ',\'' + key + '\',{';
        str += 'configurable:' + desc.configurable + ',';
        str += 'enumerable:' + desc.enumerable + ',';
        str += 'writable:' + desc.writable + ',';
        if (typeof desc.value === 'object') {
          str += 'value:v' + m.get(desc.value);
        } else {
          str += 'value:' + stringifyPrimitive(desc.value);
        }
        str += '});\n';
      }
      return str;
    }

    function cloneObjectString(obj) {
      var str = '(function() {';
      var m = new Map();
      str += buildValMap(obj, m);
      m.forEach(function(num, o) {
        str += buildObjectInternal(o, m);
      });
      return str + 'return v' + m.get(obj) + ';\n})()';
    }