Feature idea: onlyOnce method about ampersand-events

[cdaringe]

interesting. i expected the behavior you expected as well. i'm not sure that this isn't a bug*

[wraithgar]

onlyOnce makes sense as a name to me, and I wonder if once with multiple names should log a warning. I for one would have fallen into the same assumption. Agreeing w/ @cdaringe that this could even be considered a bug (the fixing of which would probably necessitate a major version however)

[dhritzkiv]

The tests indicate that isn't not a insidious bug in as much as the tests specifically expect the callback to be called for each event name. (https://github.com/AmpersandJS/ampersand-events/blob/master/test/index.js#L528)

The reason for this expectation, I believe, is Backbone's events works this way (I found out through Stackoverflow, where other devs were confused by this behaviour too). Check out this assertion example (using Backbone event instead of ampersand-events) to see for yourselves

[dhritzkiv]

What really confuses me is the expected behaviour after reading through the code logic of ampersand-event's once:

    once: function (name, callback, context) {
        var self = this;
        var once = runOnce(function () {
            self.off(name, once);
            callback.apply(this, arguments);
        });
        once._callback = callback;
        return this.on(name, once, context);
    }

it seems that callback is being wrapped inside a function that also calls off to remove this particular listener for any future events for this name, and then that function is then being wrapped in lodash.once. Not sure if that's right.