Path: csiph.com!.POSTED.204-73-239-109.cust.centrio.cz!not-for-mail
From: Cezary Tomczyk <cezary.tomczyk@gmail.com>
Newsgroups: comp.lang.javascript
Subject: Re: Object.defineProperties
Date: Fri, 5 May 2017 08:32:55 +0200
Organization: csiph.com Internet News Service
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References: <oebtq0$2611$1@csiph.com> <objects-20170503082342@ram.dialup.fu-berlin.de> <primitive-types-20170505033844@ram.dialup.fu-berlin.de>
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Xref: csiph.com comp.lang.javascript:33206

On 05/05/2017 04:39, Stefan Ram wrote:
> ram@zedat.fu-berlin.de (Stefan Ram) writes:
>> 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.
>
>   However, according to Flanagan, a host object may not
>   return »undefined«, »boolean«, »number«, or »string« as
>   its type. So, another way to check whether something is
>   an object might be to check that its type is not one
>   of those.

Yes, but typeof for [] will still returns "object".

One more thing. Regarding:

let a = new String( "abc" );

console.log( Object.prototype.toString.call( a ) );

Object.defineProperty
( a, Symbol.toStringTag, { get: function() { return "Number"; }});

console.log( Object.prototype.toString.call( a ) );

if typing "a instanceof String" then there is "true". So, perhaps 
instanceof is the way of checking the type of object instead of 
Object.prototype.toString.call or typeof or Object.defineProperty[...]

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