Can't create sprite within own fucntion

[DanielMontilla]

Trying to spawn target periodically using .time.addEvent. But the callback function won't spawn the sprite. Console spits out TypeError: this.add is undefined. I'm fairly new to JavaScript sorry. (I've placed the sprite outside of the spawnTarget function and it works fine!)

    create() {
        let targetSpawnInterval = 350;

        function spawnTarget () {
            this.add.sprite(Phaser.Math.Between(0, 600), Phaser.Math.Between(0, 800), 'target');
        };
  
        this.time.addEvent({
            delay: targetSpawnInterval,
            callback: spawnTarget,
            loop: true
        });
    }