1/*
2* The contents of this file are subject to the Netscape Public
3* License Version 1.1 (the "License"); you may not use this file
4* except in compliance with the License. You may obtain a copy of
5* the License at http://www.mozilla.org/NPL/
6*
7* Software distributed under the License is distributed on an "AS
8* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
9* implied. See the License for the specific language governing
10* rights and limitations under the License.
11*
12* The Original Code is mozilla.org code.
13*
14* The Initial Developer of the Original Code is Netscape
15* Communications Corporation.  Portions created by Netscape are
16* Copyright (C) 1998 Netscape Communications Corporation. All
17* Rights Reserved.
18*
19* Contributor(s): pschwartau@netscape.com
20* Date: 14 Mar 2001
21*
22* SUMMARY: Utility functions for testing objects -
23*
24* Suppose obj is an instance of a native type, e.g. Number.
25* Then obj.toString() invokes Number.prototype.toString().
26* We would also like to access Object.prototype.toString().
27*
28* The difference is this: suppose obj = new Number(7).
29* Invoking Number.prototype.toString() on this just returns 7.
30* Object.prototype.toString() on this returns '[object Number]'.
31*
32* The getJSType() function below will return '[object Number]' for us.
33* The getJSClass() function returns 'Number', the [[Class]] property of obj.
34* See ECMA-262 Edition 3,  13-Oct-1999,  Section 8.6.2
35*/
36//-------------------------------------------------------------------------------------------------
37var cnNoObject = 'Unexpected Error!!! Parameter to this function must be an object';
38var cnNoClass = 'Unexpected Error!!! Cannot find Class property';
39var cnObjectToString = Object.prototype.toString;
40
41
42// checks that it's safe to call findType()
43function getJSType(obj)
44{
45  if (isObject(obj))
46    return findType(obj);
47  return cnNoObject;
48}
49
50
51// checks that it's safe to call findType()
52function getJSClass(obj)
53{
54  if (isObject(obj))
55    return findClass(findType(obj));
56  return cnNoObject;
57}
58
59
60function findType(obj)
61{
62  return cnObjectToString.apply(obj);
63}
64
65
66// given '[object Number]',  return 'Number'
67function findClass(sType)
68{
69  var re =  /^\[.*\s+(\w+)\s*\]$/;
70  var a = sType.match(re);
71
72  if (a && a[1])
73    return a[1];
74  return cnNoClass;
75}
76
77
78function isObject(obj)
79{
80  return obj instanceof Object;
81}
82