Super Basic Particle System

particles.js

function setup() {
    createCanvas(windowWidth, windowHeight);
    background("red");

    let pe = new ParticleEmitter();
    pe.draw();

}

function draw() {

}

class Particle {
    // we have a blueprint.

    constructor(x, y) {
        this.size = 10;
        this.pos = createVector(x, y);  
    }

    draw() {
        ellipse(this.pos.x, this.pos.y, this.size);
    }
}

class ParticleEmitter {

    constructor() {
        this.particles = [];

        for(let i = 0; i <= 100; i++) {
            this.particles[i] = new Particle(random(windowWidth), random(windowHeight));
        }

    }

    draw() {
        for(let i = 0; i <= 100; i++) {
            this.particles[i].draw();
        }
    }
}