Create an object with dynamic property names [duplicate]

Question

I am trying to do this:

var KEYS = {} ;

KEYS.PHONE_TYPE = 'phone-type';
KEYS.AGENT_TYPE = 'agent-type';

var myAppConfig = {
    ...
    iconMap : { 
        KEYS.PHONE_TYPE : 'icon-phone', 
        KEYS.AGENT_TYPE : 'icon-headphones'
    };
    ...
};

But it is failing, with a message: Expected ':' and instead saw '.'.

How can I initialize an object using indirect (non-literal) keynames?

To be clear, the result I want is:

{
    'phone-type' : 'icon-phone',
    'agent-type' : 'icon-headphones'
}

and Use a concatenated (dynamic) string as JavaScript object key? — Felix Kling
– Felix Kling, Commented Jul 24, 2013 at 11:27
and Is it possible to add dynamically named properties to JavaScript object? — Felix Kling
– Felix Kling, Commented Jul 24, 2013 at 11:28
I guess I get your point! :) But I assure you I looked for it before! — blueFast
– blueFast, Commented Jul 24, 2013 at 11:34

Dragos Bobolea · Accepted Answer · 2016-08-25 14:30:43Z

14

If you're using ES6 (or something like Babel/browserify), you can write it like this:

iconMap : { 
    [KEYS.PHONE_TYPE] : 'icon-phone', 
    [KEYS.AGENT_TYPE] : 'icon-headphones'
};

answered Aug 25, 2016 at 14:30

Dragos Bobolea

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Comments

Sirko · Accepted Answer · 2013-07-24 11:25:34Z

7

You would have to add those properties separately using bracket notation:

var myAppConfig = {
    ...
    iconMap : { }
    ...
};

myAppConfig.iconMap[ KEYS.PHONE_TYPE ] = 'icon-phone';
myAppConfig.iconMap[ KEYS.AGENT_TYPE ] = 'icon-headphones';

answered Jul 24, 2013 at 11:25

Sirko

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2 Comments

blueFast Over a year ago

Thanks. I am still surprised that javascript has no built-in support for initialization of an object with dynamic keynames. Python can do this for dictionaries, and it is very convenient. I guess this comes from the fact that the quotes are optional in javascript properties.

Petruza Over a year ago

I guess JS abandoned that possibility by allowing unquoted attribute names, Python avoids this by requiring quoted attribute names.

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