`BaseTween#callbacks` type is inconsistent with runtime behaviour

[Bertie690]

Version

• Phaser Version: N/A (Occurs on master)
• Operating system: N/A
• Browser: N/A

Description

The type for callbacks is incorrect - instead of a partial object that might have each callback, it's an object that ALWAYS has every single callback (though each may be set to null).

phaser/src/tweens/tween/BaseTween.js

Lines 220 to 231 in 41be1e4

	this.callbacks = {
	onActive: null,
	onComplete: null,
	onLoop: null,
	onPause: null,
	onRepeat: null,
	onResume: null,
	onStart: null,
	onStop: null,
	onUpdate: null,
	onYoyo: null
	};

MOREOVER, the data added by setCallback is NOT a simple lambda function! It's an object containing the extra parameters!

phaser/src/tweens/tween/BaseTween.js

Lines 621 to 624 in 41be1e4

	if (this.callbacks.hasOwnProperty(type))
	{
	this.callbacks[type] = { func: callback, params: params };
	}

This is BLATANTLY type-unsafe due to effectively misrepresenting the type's very nature - the declaration file says "record of lambda functions", the code says "record of objects with lambda functions".

Current (incorrect) typing

type TweenCallbacks = {
  /**
   * A function to call when the tween becomes active within the Tween Manager.
   */
  onActive?: Phaser.Types.Tweens.TweenOnActiveCallback;
  /**
   * A function to call when the tween starts playback, after any delays have expired.
   */
  onStart?: Phaser.Types.Tweens.TweenOnStartCallback;
  /**
   * A function to call when the tween completes.
   */
  onComplete?: Phaser.Types.Tweens.TweenOnCompleteCallback;
  /**
   * A function to call each time the tween loops.
   */
  onLoop?: Phaser.Types.Tweens.TweenOnLoopCallback;
  /**
   * A function to call each time the tween is paused.
   */
  onPause?: Phaser.Types.Tweens.TweenOnPauseCallback;
  /**
   * A function to call each time the tween is resumed.
   */
  onResume?: Phaser.Types.Tweens.TweenOnResumeCallback;
  /**
   * A function to call each time the tween repeats. Called once per property per target.
   */
  onRepeat?: Phaser.Types.Tweens.TweenOnRepeatCallback;
  /**
   * A function to call when the tween is stopped.
   */
  onStop?: Phaser.Types.Tweens.TweenOnStopCallback;
  /**
   * A function to call each time the tween steps. Called once per property per target.
   */
  onUpdate?: Phaser.Types.Tweens.TweenOnUpdateCallback;
  /**
   * A function to call each time the tween yoyos. Called once per property per target.
   */
  onYoyo?: Phaser.Types.Tweens.TweenOnYoyoCallback;
};

Example Test Code

const tween = scene.tweens.add({targets: sprite, duration: 400, on});
if (tween.callbacks.onComplete === null) {} // TS says impossible, but actually runs
tween.callbacks.onComplete?.() // CRASHES because it's not a function!

Additional Information

The callbacks themselves should also probably be readonly, given the setCallback function's entire purpose is to modify them.