Null Object Reference error when coding a custom event (mod-folder)

[MAZ12211]

For context I wanted to create a custom event that rotates the camera with ease effects much like base game
I have no clue what causes this error, I've reread it several times for a missing semicolon but I got nothing
V0.5.3

// Mostly copied from source code lol
import funkin.play.PlayState;
import funkin.Conductor;
import funkin.modding.events.ScriptEvent;
import funkin.modding.module.Module;
import funkin.ui.AtlasText;
import flixel.FlxG;
import flixel.tweens.FlxTween;
import flixel.util.FlxTimer;
import flixel.tweens.FlxEase;
import flixel.FlxCamera;
import funkin.graphics.FunkinSprite;
import funkin.Paths;
import openfl.utils.Assets;
// import Reflect; Had no clue it was blacklisted, so I used ReflectUtil instead
import funkin.util.ReflectUtil;
import funkin.play.event.SongEvent;

class CameraRotateEvent extends SongEvent {
    function new() {
        super("cameraRotateEvent");
    }
    public var DEFAULT_ANGLE:Float = 45.0;
    public var DEFAULT_DURATION:Float = 4.0;
    public var DEFAULT_EASE:String = 'linear';

    public var cameraTween:FlxTween = null;

    public override function handleEvent(data:SongEventData):Void {
        if (PlayState.instance == null || PlayState.instance.currentStage == null) return;
        
        // Does nothing if we are minimal mode.
        if (PlayState.instance.isMinimalMode) return;

        var duration:Float = data.getFloat('duration') != null ? data.getFloat('duration') : DEFAULT_DURATION;
        var toAngle:Float = data.getFloat('angle') != null ? data.getFloat('angle') : DEFAULT_ANGLE;
        var ease:String = data.getString('ease') != null ? data.getString('ease') : DEFAULT_EASE;
        
        switch (ease) {
            case 'INSTANT':
              // Cancel the tween here, so it doesn't tween (haven't tested it yet)
              cameraTween.cancel();
            default:
                var durSeconds = Conductor.instance.stepLengthMs * duration / 1000;
                var easeFunction:Null<Float->Float> = ReflectUtil.getAnonymousField(FlxEase, ease);
        }
        
        rotateCamGame(toAngle, duration, easeFunction);
    }

    public function rotateCamGame(?toAngle:Float, ?duration:Float, ?ease:Null<Float->Float>):Void {
      // Doc says normal tweenning isn't recommended for this case, so I used FlxTween.angle 
      cameraTween = FlxTween.angle(PlayState.instance.camGame, PlayState.instance.camGame.angle, toAngle, duration, {ease: easeFunction});
    }

    public override function getTitle() {
        return 'Camera Rotate';
    }

    public override function getEventSchema()
        {
          return [
            {
              name: 'angle',
              title: 'angle',
              defaultValue: 45.0,
              step: 0.1,
              type: "float",
              units: 'x'
            },
            {
              name: 'duration',
              title: 'Duration',
              defaultValue: 4.0,
              step: 0.5,
              type: "float",
              units: 'steps'
            },
            {
              name: 'ease',
              title: 'Easing Type',
              defaultValue: 'linear',
              type: "enum",
              keys: [
                'Linear' => 'linear',
                'Instant (Ignores Duration)' => 'INSTANT',
                'Sine In' => 'sineIn',
                'Sine Out' => 'sineOut',
                'Sine In/Out' => 'sineInOut',
                'Quad In' => 'quadIn',
                'Quad Out' => 'quadOut',
                'Quad In/Out' => 'quadInOut',
                'Cube In' => 'cubeIn',
                'Cube Out' => 'cubeOut',
                'Cube In/Out' => 'cubeInOut',
                'Quart In' => 'quartIn',
                'Quart Out' => 'quartOut',
                'Quart In/Out' => 'quartInOut',
                'Quint In' => 'quintIn',
                'Quint Out' => 'quintOut',
                'Quint In/Out' => 'quintInOut',
                'Expo In' => 'expoIn',
                'Expo Out' => 'expoOut',
                'Expo In/Out' => 'expoInOut',
                'Smooth Step In' => 'smoothStepIn',
                'Smooth Step Out' => 'smoothStepOut',
                'Smooth Step In/Out' => 'smoothStepInOut',
                'Elastic In' => 'elasticIn',
                'Elastic Out' => 'elasticOut',
                'Elastic In/Out' => 'elasticInOut'
              ]
            }
          ];
        }
}

[KoloInDaCrib]

I think it's cuz you defined easeFunction only in the default case

my proposed changes would be to define easeFunction outside the switch block (with a null value as a start value) and then set it to a value in the default case instead of defining it there

[MAZ12211]

Like this?
While this resolves the error, the event doesn't work in-game at all. no camera rotation at all and no error pop ups too

public override function handleEvent(data:SongEventData):Void {
        if (PlayState.instance == null || PlayState.instance.currentStage == null) return;
        
        // Does nothing if we are minimal mode.
        if (PlayState.instance.isMinimalMode) return;

        var duration:Float = data.getFloat('duration') != null ? data.getFloat('duration') : DEFAULT_DURATION;
        var toAngle:Float = data.getFloat('angle') != null ? data.getFloat('angle') : DEFAULT_ANGLE;
        var ease:String = data.getString('ease') != null ? data.getString('ease') : DEFAULT_EASE;
        var easeFunction:Null<Float->Float> = null;

        switch (ease) {
            case 'INSTANT':
              // Cancel the tween here, so it doesn't tween (haven't tested it yet)
              cameraTween.cancel();
            default:
              var durSeconds = Conductor.instance.stepLengthMs * duration / 1000;
              // var easeFunction:Null<Float->Float> = ReflectUtil.getAnonymousField(FlxEase, ease);
              easeFunction = ReflectUtil.getAnonymousField(FlxEase, ease);
            }
        
        rotateCamGame(toAngle, duration, easeFunction);
    }

    public function rotateCamGame(?toAngle:Float, ?duration:Float, ?ease:Null<Float->Float>):Void {
      // Doc says normal tweenning isn't recommended for this case, so I used FlxTween.angle 
      cameraTween = FlxTween.angle(PlayState.instance.camGame, PlayState.instance.camGame.angle, toAngle, duration, {ease: ease});
    }

[Lasercar]

When it's INSTANT, you really need to do it instantly:

public override function handleEvent(data:SongEventData):Void {
        if (PlayState.instance == null || PlayState.instance.currentStage == null) return;
        
        // Does nothing if we are minimal mode.
        if (PlayState.instance.isMinimalMode) return;

        var duration:Float = data.getFloat('duration') != null ? data.getFloat('duration') : DEFAULT_DURATION;
        var toAngle:Float = data.getFloat('angle') != null ? data.getFloat('angle') : DEFAULT_ANGLE;
        var ease:String = data.getString('ease') != null ? data.getString('ease') : DEFAULT_EASE;
        var easeFunction:Null<Float->Float> = null;

        switch (ease) {
            case 'INSTANT':
              // Cancel the tween here, so it doesn't tween (haven't tested it yet)
              cameraTween.cancel();
              // It's a snap!
              PlayState.instance.camGame.angle = toAngle;
            default:
              easeFunction = ReflectUtil.getAnonymousField(FlxEase, ease);
              if (easeFunction == null)
              {
                trace('Invalid ease function: $ease');
                return;
              }
              rotateCamGame(toAngle, duration, easeFunction);
            }
    }

Basically, there's no need to tween it. Only use a tween if the duration isn't zero.
durSeconds is also an unused variable, as I'm guessing you copied it or looked at how an existing event works, so there's no need for it.