ImpactJS particle generator, requires a particle class passed to it in order to work.

particle-generator.js

ig.module(
    'game.entities.particle-generator'
)
.requires(
    'impact.entity'
)
.defines(function(){
    'use strict';

    // @TODO Must use pooling for individual particles
    window.EntityParticleGenerator = ig.Entity.extend({
        // Width and height are the distribution radius
        size: { x: 50, y: 50 },

        // Type of particle to create
        particleClass: null,

        // @TODO Should be a range, not a set value
        // Total number of particles to distribute
        particles: 6,

        // How many seconds to keep the particle generator alive before destroying
        lifetime: 2,

        // Make this particle generator run infinitely
        repeat: false,

        // Create all particles at one time and destroy immediately, performance intensive
        instant: false,

        init: function( x, y, settings ) {
            this.parent( x, y, settings );

            // Force generate all particles
            if (this.instant) {
                for (var i = 0; i < this.particles; i++) {
                    this.createParticle();
                }

                this.kill();
                return;
            }

            // Create a timer that generates a particle every time it expires
            this.timerGenerate = new ig.Timer();
            this.timerGenerate.set(this.lifetime / this.particles);

            // Create an expiration timer
            this.timerExpire = new ig.Timer();
            this.timerExpire.set(this.lifetime);
        },

        update: function () {
            if (this.timerExpire.delta() > 0) {

                if (this.repeat === true) {
                    this.timerExpire.reset();
                } else {
                    this.kill();
                }

            } else if (this.timerGenerate.delta() > 0) {
                this.createParticle();
                this.timerGenerate.reset();
            }
        },

        // Generates a particle within the particle generator's bounds
        createParticle: function () {
            ig.game.spawnEntity(this.particleClass, this.pos.x + ig.game.calc.random(0, this.size.x), this.pos.y + ig.game.calc.random(0, this.size.y));
        }
    });
});