Again, I partially agree. You have to figure out what it means only if you're *not sure* about your code quility.

> I have a method called `this._dragging()`, but I'm not sure if it's been defined yet!

No, because you would have wrote `typeof this._dragging === 'undefined'`.

> I have an string stored in this._dragging, but I'm not sure whether it's empty or not!

No, because you would have wrote `this._dragging.length === 0`.

Anyway I agree with you that using `=== true` banishes all doubts.

Note: I'm not trying to remove `=== true` to save eight characters but only for a matter of readability.