Units that were able to reach the last point on the path should take one life from the player and disappear from the game. Let’s add a call to the processCompletedEnemies method at the beginning of the update method in the Game class:

    processCompletedEnemies() {
        const enemy = this.enemies.units.find(enemy => enemy.isOutOfTheScreen);

        if (enemy) {
            enemy.remove();
            --this.player.lives;
            this.checkGameOver();
        }
    }
    update() {
        this.processCompletedEnemies();
        // ...
    }

Let’s implement the isOutOfTheScreen getter:

    get isOutOfTheScreen() {
        if (this.pathIndex === this.path.length) {
            let point = this.sprite.getGlobalPosition();

            if (point.x < 0 ||point.x > App.app.view.width) {
                return true;
            }
        }


        return false;
    }

Here we make sure to check whether the enemy unit has reached its final point:

this.pathIndex === this.path.length

And if the final point is reached, then it is enough to check the positions using one of the sprite coordinates.

Let’s add the checkGameOver method to the Game class. We will restart the game if the player has lost all lives:

    checkGameOver() {
        if (this.player.lives <= 0) {
            alert("Game Over!");
            App.scenes.start("Game");
        }
    }