Javascript Objects (dynamic attribute names) -

if have object, this

var o = {   test : 1 } 

and have second object, 1 of it's keys should value of o.test. this:

var o2 = {    o.test : "bla" } 

i know not possible, there better (cleaner) way do now?

currently dow this:

var o2 = {}; o2[o.test] = "bla" 

i guess there better way this?

i guess there better way this?

assuming i've understood question correctly no, not really. way you've shown way it. there no way use dynamic key inside literal itself, have declare first , assign property separately:

var o2 = {}; o2[o.test] = "bla";  o2; // { 1: "bla" } 

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update

the full details given in spec. here's grammar object literal property identifiers:

propertyname :
    identifiername
    stringliteral
    numericliteral

the stringliteral production self-explanatory. here's identifiername production does:

the production propertyname : identifiername evaluated follows:

1. return string value containing same sequence of characters identifiername.

and numericliteral production:

the production propertyname : numericliteral evaluated follows:

1. let nbr result of forming value of numericliteral.
2. return tostring(nbr).

you can see not possible use other string inside object initialiser.