ECSArticle

particles.js

function createParticle(px, py, vx, vy, lifespan) {
    return {
        type: "Particle",
        x: px,
        y: py,
        vx,
        vy,
        age: 0,
        lifespan,
        alive: true
    }
}

function updateParticle(particle) {
    particle.x += particle.vx
    particle.y += particle.vy
    particle.alive = particle.age++ < particle.lifespan
    return particle
}

...

particles = particles
    .map(updateParticle)
    .filter(p => p.alive)