tests/mozilla/ecma_3/Object/shell.js

   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 //-------------------------------------------------------------------------------------------------
  37 var cnNoObject = 'Unexpected Error!!! Parameter to this function must be an object';
  38 var cnNoClass = 'Unexpected Error!!! Cannot find Class property';
  39 var cnObjectToString = Object.prototype.toString;
  40
  41
  42 // checks that it's safe to call findType()
  43 function 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()
  52 function getJSClass(obj)
  53 {
  54   if (isObject(obj))
  55     return findClass(findType(obj));
  56   return cnNoObject;
  57 }
  58
  59
  60 function findType(obj)
  61 {
  62   return cnObjectToString.apply(obj);
  63 }
  64
  65
  66 // given '[object Number]',  return 'Number'
  67 function 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
  78 function isObject(obj)
  79 {
  80   return obj instanceof Object;
  81 }