When iterating with a for loop it's more convenient to use this:

```
for (var key in obj){ key }

```

than these:

```
for (var i in array){ var key = array[i]; key }
for (var i = 0; i< array.length;i++){ var key = array[i]; key }

```

But, obviously, declaring arrays is easier:

```
var array = ['key1', 'key2', 'key3']

var obj =   { key1:'',key2:'',key3:'' }

```

Assuming I only care about keys and don't care about order, is there a way of declaring objects with just keys and no values (more easily than above)? I just don't like using

```
:'',    

```

It looks like a weird smiley face.

Edit:
`for-of` would definitely be the way to go, just not yet.