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/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/*---
defines: [getJSClass, findType, findClass, isObject]
allow_unused: True
---*/
/*
* Date: 14 Mar 2001
*
* SUMMARY: Utility functions for testing objects -
*
* Suppose obj is an instance of a native type, e.g. Number.
* Then obj.toString() invokes Number.prototype.toString().
* We would also like to access Object.prototype.toString().
*
* The difference is this: suppose obj = new Number(7).
* Invoking Number.prototype.toString() on this just returns 7.
* Object.prototype.toString() on this returns '[object Number]'.
*
* The getJSClass() function returns 'Number', the [[Class]] property of obj.
* See ECMA-262 Edition 3, 13-Oct-1999, Section 8.6.2
*/
//-----------------------------------------------------------------------------
var cnNoObject = 'Unexpected Error!!! Parameter to this function must be an object';
var cnNoClass = 'Unexpected Error!!! Cannot find Class property';
var cnObjectToString = Object.prototype.toString;
var GLOBAL = 'global';
// checks that it's safe to call findType()
function getJSClass(obj)
{
if (isObject(obj))
return findClass(findType(obj));
return cnNoObject;
}
function findType(obj)
{
return cnObjectToString.apply(obj);
}
// given '[object Number]', return 'Number'
function findClass(sType)
{
var re = /^\[.*\s+(\w+)\s*\]$/;
var a = sType.match(re);
if (a && a[1])
return a[1];
return cnNoClass;
}
function isObject(obj)
{
return obj instanceof Object;
}