Javascript object property with variable name

Question

I never thought I'd stumble in a problem like that but hey what do you know..

var prop = 'horses'

console.log({
    prop: 1
});

How can I have this produce an object with a property horses instead of prop and possibly have it done in a single line? Because I can think of a solution but what I'm really looking for is a one-liner.

truely one-liner: `var prop = "horses"; console.log((function(o,p){o[p]=1;return o;})({},prop));` — Tomasz Gawel, Dec 22 '13 at 22:25

score 3 · Accepted Answer · answered Dec 22 '13 at 22:16

You can use bracketed notation:

var obj = {};
obj[prop] = 1;
console.log(obj);

In JavaScript, you can refer to a property either by dot notation and a literal name (foo.bar), or bracketed notation with a string name (foo["bar"]). In the latter case, the string can be the result of any expression, including (in your case) a variable reference.

...but what I'm really looking for is a one-liner.

There's no way to do that as part of an object initializer, though, you have to do it separately. If you want a one-liner, you'll need to do a function call, e.g.:

console.log(makeObj(prop, 1));

where makeObj is

function makeObj(propName, propValue) {
    var obj = {};
    obj[propName] = propValue;
    return obj;
}

score 1 · Answer 2 · answered Dec 22 '13 at 22:16

1

Try using JSON to create the object:

console.log(JSON.parse("{\"" + prop + "\":\"1\"}");

answered Dec 22 '13 at 22:16

Bic

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There's no need to fire up a JSON parser for this. Creative, though. – T.J. Crowder Dec 22 '13 at 22:17

Javascript object property with variable name

2 Answers2