Tween Duration Is Set To Zero When Created

Phaser 3
1

If you make a tween and immediately check its duration, it will return 0 regardless of the actual duration value set.

Example here: https://jsbin.com/qegofadogo/edit?html,js,output

Is this intended? I’d like to measure the duration of multiple tweens and trigger an event after the last one is done.

2

In the example tween.duration is printed before tween creation, you can get the duration in the same function using a timeout for example:

 function create () {

    let testObj = {
        tweenProperty: 0
    }

    tween = this.add.tween({
        targets: testObj,
        tweenProperty: 100,
        duration: 2000,
        onComplete: tweenComplete
    })
    setTimeout(()=>console.log('Tween duration: ' + tween.duration),1)
    
}
3

If the duration was printed before the tween was actually created, then wouldn’t you get an error or undefined rather than printing a zero? If I move the console.log line above the tween creation I get ‘tween is not defined’.

4

I think only the keys of the Tween object are passed on declaration, and the values are passed once the tween starts.

function create () {

    let testObj = {
        tweenProperty: 0
    }

    tween = this.add.tween({
        targets: testObj,
        tweenProperty: 100,
        duration: 2000,
        onComplete: tweenComplete,
        onStart:()=>console.log(tween.duration)
    })
    
}
5

The same thing happens if you make a tween manually with the Phaser.Tweens.Tween() class. I wonder if there’s a reason it’s done this way in Phaser. I’ll just find a workaround in the meantime.

6

I would use a timeline for that, or else several tween onComplete callbacks.

Tween durations are calculated when the tween is started.