Path: csiph.com!aioe.org!.POSTED!not-for-mail
From: Joao Rodrigues <groups_jr-1@yahoo.com>
Newsgroups: comp.lang.javascript
Subject: Re: undefined string in an object?
Date: Sat, 9 Sep 2017 11:07:18 -0300
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JRough wrote:
> me (JRough change)
> 
> 4:31 PM (less than a minute ago)
> 
> 
> var a={}; a["b"]=123, a["c"]=456; console.log(a["b"]); undefined
> 
> var a={}; a.b=123, a.c=456; console.log(a.b); undefined
> 
> 
> Why is this object literal not defined?  If it is because it was
> stringified how to make it an object again so you get the value?
> tnx,
> 

This object literal is being defined accordingly.
var a = {};
a["b"]=123, a["c"]=456;
          ^^^

There you have used the comma operator, maybe unwittingly, but it was ok 
in this case.
<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comma_Operator>

console.log(a["b"]) is returning "123", and then undefined.

If you write console.log(a) or console.dir(a), you'll retrieve:
{ b: 123, c: 456 }

See also 
<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Property_Accessors>

-- 
Joao Rodrigues