Getting the first index of an object

Just for fun this works in JS 1.8.5

var obj = {a: 1, b: 2, c: 3};
Object.keys(obj)[0]; // "a"

This matches the same order that you would see doing

for (o in obj) { ... }

they're not really ordered, but you can do:

var first;
for (var i in obj) {
    if (obj.hasOwnProperty(i) && typeof(i) !== 'function') {
        first = obj[i];
        break;
    }
}

the .hasOwnProperty() is important to ignore prototyped objects.

If you want something concise try:

for (first in obj) break;

alert(first);

wrapped as a function:

function first(obj) {
    for (var a in obj) return a;
}

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