Key for javascript dictionary is not stored as value but as variable name

Question

I'm trying to create a dictionary object like so

var obj = { varName : varValue }; 

What I'm expecting is if varName='foo', the obj should be {'foo', 'some value' } however what I see is {varName, 'some value'} the value of variable is not being used but a variable name as a key. How do I make it so that varible value is used as key?

Answer 1

Try like this:

var obj = {}; obj[varName] = varValue; 

You can't initialize objects with 'dynamic' keys in old Javascript. var obj = { varName : varValue }; is equivalent to var obj = { "varName" : varValue };. This is how Javascript interprets.

However new ECMAScript supports computed property names, and you can do:

var obj = { [varName]: varValue };