A particle system built for Canvas 2D that's simple to use and customize. The main focus is performance with batch rendering, minimal color state changes with a predefined palette, object pooling with separate pools for explosions and particles to reduce garbage collection hits, efficient object sorting, and simplifying the particles' shape as they shrink.

1. The particle system is initialized by calling particles.init().
2. Your tick/render loop needs to include:

explosions.update();
particles.draw();

3. Explosions can be spawned by using:

const explosion = explosions.create();
explosion.init(/* X position */, /* Y position */);

The basic settings can be changed in the explosion object:

const explosion = {
    colors: ['#6434E9', '#2C7CE5', '#49CC5C', '#F8C421', '#FB6640', '#F82553'],
    variations: 6,
    multiplier: 8
};

variations corresponds to how many color indices present in the colors array, while multiplier decides how many particles spawn per color index (e.g. 6 * 8 = 48 particles per explosion).

How the particles behave can be changed in the Particle class' init function:

init(x, y) {
    this.x = x;
    this.y = y;
    const direction = Math.random() * Math.PI * 2;
    const velocity = Math.random() * 3.5;
    this.vx = Math.cos(direction) * velocity;
    this.vy = Math.sin(direction) * velocity;
    this.wither = Math.random() * 0.007 + 0.007;
    this.radius = 2 + Math.random() * 4;
    this.dead = false;
}

direction shapes the explosion. velocity/radius gives the particles their speed and initial radius. wither sets the constant rate at how fast the particles' radius decreases. Note: the wither value should be randomized to spread out pooling operations.