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From: Cezary Tomczyk <cezary.tomczyk@gmail.com>
Newsgroups: comp.lang.javascript
Subject: Re: Object.defineProperties
Date: Sat, 6 May 2017 23:05:55 +0200
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Xref: csiph.com comp.lang.javascript:33242

On 06/05/2017 22:37, Stefan Weiss wrote:
> Cezary Tomczyk wrote:
>>         if (typeToCheck === 'array' && Array.isArray(obj)
>>             || typeToCheck === 'null' && objectType === 'object'
>>             || typeToCheck === 'object' && objectType === 'object'
>
> So any object except an Array tests positive for "null" - is that intentional?
>
>   isTypeOf({}, "null")  →  true
>
> Also, if you're going to such lengths, you might as well include the
> "function" type in the conditional.
>
> On the whole, I'm not convinced that this function is very useful in
> practice. I can't think of many situations where I would consider `false`
> and `new Boolean(false)` as having the same "type". They're certainly not
> interchangable. The `typeof` operator and `Array.isArray()` are usually all
> that's needed.

You're right. I've simplified it. Aparat of 'typeof' operator, 
'Array.isArray()' I need to cover 'null' case.

     function isTypeOf(obj, typeToCheck) {
         var type;

         if (arguments.length < 2) {
             throw new Error('[isTypeOf] requires two arguments');
         }

         type = typeToCheck.toLowerCase();

         if (type === 'null' && obj === null) {
             return 'null';
         }

         if (type === 'array' && Array.isArray(obj)) {
             return 'array';
         }

         return typeof obj === type;
     }

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