[Solved] Tweening a property sets the value to NaN?!

[QLNEO]

What I'm trying to do is to set an internal value to change via a tween invoked inside that same object. IDK if that's even legal but that's what I'm doing right now.

class TheObject extends Phaser.Sprite {
    constructor() {
        ...
        this.circleAngle = 90;
        game.add.tween(this)
        .to({circleAngle: 360}, this.period*1000, null, true, 1000, -1)
        .onUpdateCallback(function(tween, value) {
            console.log(value); // NaN!
        })
    }
}

The idea is to loop circleAngle continously, but all the tween's doing is NaNing it. Any ideas on how to make it really interpolate as I intended?

[Skeptron]

Are you sure this.period is correctly defined?

[QLNEO]

13 minutes ago, Skeptron said:

Are you sure this.period is correctly defined?

It wasn't, of course. I forgot to fix the name.
Huge thanks!