CloudInvaders/bullet.js

class Bullet extends Entity {
    constructor(x, y) {
        super(x, y, 0.001, 0.02);
        this.element.className = 'bullet';
    }

    update() {
        if (this.alive) {
            this.y -= 0.01;
            if (this.y < -0.1) {
                this.destroy();
            }

            for (let cloud of clouds) {
                if (this.isOverlapped(cloud)) {
                    cloud.destroy();
                    this.destroy();
                }
            }
        }
    }
}

class RainDrop extends Bullet {
    constructor(x, y) {
        super(x, y);
        this.element.className = 'raindrop';
    }

    update() {
        if (this.alive) {
            this.y += 0.01;
            if (this.y > 1.1) {
                this.destroy();
            } else if (this.isOverlapped(shootingPad)) {
                gameOver('Game over');
                this.destroy();
            }
        }
    }
}