prototype/src/lang/object.js

(function() {
  function extend(destination, source) {
    for (var property in source)
      destination[property] = source[property];
    return destination;
  }

  function inspect(object) {
    try {
      if (isUndefined(object)) return 'undefined';
      if (object === null) return 'null';
      return object.inspect ? object.inspect() : String(object);
    } catch (e) {
      if (e instanceof RangeError) return '...';
      throw e;
    }
  }

  function toJSON(object) {
    var type = typeof object;
    switch (type) {
      case 'undefined':
      case 'function':
      case 'unknown': return;
      case 'boolean': return object.toString();
    }

    if (object === null) return 'null';
    if (object.toJSON) return object.toJSON();
    if (isElement(object)) return;

    var results = [];
    for (var property in object) {
      var value = toJSON(object[property]);
      if (!isUndefined(value))
        results.push(property.toJSON() + ': ' + value);
    }

    return '{' + results.join(', ') + '}';
  }

  function toQueryString(object) {
    return $H(object).toQueryString();
  }

  function toHTML(object) {
    return object && object.toHTML ? object.toHTML() : String.interpret(object);
  }

  function keys(object) {
    var results = [];
    for (var property in object)
      results.push(property);
    return results;
  }

  function values(object) {
    var results = [];
    for (var property in object)
      results.push(object[property]);
    return results;
  }

  function clone(object) {
    return extend({ }, object);
  }

  function isElement(object) {
    return !!(object && object.nodeType == 1);
  }

  function isArray(object) {
    return object != null && typeof object === "object" &&
      'splice' in object && 'join' in object;
  }

  function isHash(object) {
    return object instanceof Hash;
  }

  function isFunction(object) {
    return typeof object === "function";
  }

  function isString(object) {
    try {
      return typeof (object && object.valueOf()) === "string";      
    } catch(e) {
      return false;
    }
  }

  function isNumber(object) {
    try {
      return typeof (object && object.valueOf()) === "number";
    } catch(e) {
      return false;
    }
  }

  function isUndefined(object) {
    return typeof object === "undefined";
  }

  extend(Object, {
    extend:        extend,
    inspect:       inspect,
    toJSON:        toJSON,
    toQueryString: toQueryString,
    toHTML:        toHTML,
    keys:          keys,
    values:        values,
    clone:         clone,
    isElement:     isElement,
    isArray:       isArray,
    isHash:        isHash,
    isFunction:    isFunction,
    isString:      isString,
    isNumber:      isNumber,
    isUndefined:   isUndefined
  });
})();