Blinking Sprite

//lastest version 11/15/2020
////////This class takes in key and makes it blink and glow.  The glow is a duplicate of the sprite placed behind and slightly larger
///called like this: var blinker = new Blinker(this,100,100,"booton","0xff00ff",2,500);
class Blinker extends  Phaser.GameObjects.Sprite{
    constructor(scene, x, y, key, color,invScale,timeDelay){
        super(scene, x, y, key);
        this.scene = scene; //the scene this game object will be added to
        this.scene.events.on('update', (time, delta) => { this.update(time, delta)} );// this line forces the parent scene to call the update inside this class
        this.x = x;  //x
        this.y = y;  //y
        this.key = key; //image key
        this.timeDelay = timeDelay //controls blink timing
        this.invScale = invScale; //this adjusts the size of the sprite while blinking-not sure why I did it inverted
        this.color = color;//this is for color
        this.direction = false; //controls if the blink expands or contracts
        //this.scene.physics.world.enable(this); //adds the objects to the physics world
        this.scene.add.existing(this);//adds the objects to the scene
        this.create();
    }

    create(){
        this.timedEvent = this.scene.time.addEvent({ delay: this.timeDelay, loop:true,callbackScope: this, callback: this.switch});//main loop to control the blink timing
        this.setTint(this.color).setAlpha(1);//colors the sprite
        this.backImage = this.scene.add.image(this.x,this.y, this.key).setTint(this.color).setAlpha(0.4);//duplicate image glows behind the sprite
    }

    update(){
        if(this.direction){ //contracting blink
            var scaler = this.timedEvent.getElapsed()/(this.timeDelay*this.invScale);
            this.setScale(scaler);
            this.backImage.setScale(scaler*1.5);
        }
        else{ //or expanding blink
            var scaler = this.timedEvent.getElapsed()/(this.timeDelay*this.invScale);
            var invsScaler = this.timeDelay/(this.timeDelay*this.invScale)-scaler;
            this.setScale(invsScaler);
            this.backImage.setScale(invsScaler*1.5)

        }


    }
    switch(){this.direction = !this.direction}//timer calls this function to change from grow to shrink
}