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From: Cezary Tomczyk <cezary.tomczyk@gmail.com>
Newsgroups: comp.lang.javascript
Subject: Re: Object.defineProperties
Date: Wed, 3 May 2017 10:14:24 +0200
Organization: csiph.com Internet News Service
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On 03/05/2017 09:24, Stefan Ram wrote:
> Cezary Tomczyk <cezary.tomczyk@gmail.com> writes:
>> Native built-in Object.defineProperties method allows me to add
>> properties to a function as the function is an object.
>
>   The Web gives:
>
> function isObject(val) {
>     if (val === null) { return false;}
>     return ( (typeof val === 'function') || (typeof val === 'object') );
> }
>
>   . The above might not work with host objects, which might
>   have even other types. So another suggestion from the Web is:
>
> function isObject(obj) {
>   return obj === Object(obj);
> }
>
>   The directly above might be used by underscore.js.
>
>   Other observations:
>
>   Object.getPrototypeOf does /not/ throw when called with an object.

I use:

     function isTypeOf(obj, typeToCheck) {
         if (arguments.length < 2) {
             return false;
         }
         return Object.prototype.toString.call(obj).slice(8, 
-1).toLowerCase() === typeToCheck.toLowerCase();
     }

which gives me more precisely a type of object.

The Object.defineProperties says about object, but function, array are 
also objects. That's why:

   if (typeof obj !== 'object' || obj === null)
     throw new TypeError('bad obj');

looks like a bug to me.

-- 
Cezary Tomczyk
http://www.ctomczyk.pl/
https://www.aslint.org/ - Accessibility validation tool