How to use the proton-engine.Rate function in proton-engine

createProton(canvas, width, height) {
    this.proton = new Proton();

    const emitter = new Proton.Emitter();
    emitter.damping = 0.008;
    emitter.rate = new Proton.Rate(this.props.num ? this.props.num : 150);

    // Initialize
    emitter.addInitialize(new Proton.Mass(1));
    emitter.addInitialize(new Proton.Radius(8));
    emitter.addInitialize(
      new Proton.V(new Proton.Span(0.1, 0.5), new Proton.Span(0, 360), "polar")
    );
    emitter.addInitialize(
      new Proton.Position(
        new Proton.CircleZone(canvas.width / 2, canvas.height / 2, 100)
      )
    );

    // Behaviour
    const crossZoneBehaviour = new Proton.CrossZone(
      new Proton.RectZone(0, 0, canvas.width, canvas.height),

createProton(canvas, width, height) {
    this.proton = new Proton();

    const emitter = new Proton.Emitter();
    emitter.damping = 0.008;
    emitter.rate = new Proton.Rate(this.props.num ? this.props.num : 50);
    emitter.addInitialize(new Proton.Mass(1));
    emitter.addInitialize(new Proton.Radius(5, 9));
    emitter.addInitialize(
      new Proton.Velocity(
        new Proton.Span(1.5),
        new Proton.Span(0, 360),
        "polar"
      )
    );
    emitter.addInitialize(
      new Proton.Position(new Proton.RectZone(0, 0, width, height))
    );

    const mouseInfo = {
      x: width / 2,
      y: height / 2

createProton(canvas, width, height) {
    this.proton = new Proton();
    const emitter = new Proton.Emitter();
    emitter.rate = new Proton.Rate(
      this.props.num ? new Proton.Span(this.props.num) : new Proton.Span(4, 8),
      new Proton.Span(0.1, 0.25)
    );

    emitter.addInitialize(new Proton.Mass(1));
    emitter.addInitialize(new Proton.Radius(20, 200));
    emitter.addInitialize(new Proton.Life(2, 4));
    emitter.addInitialize(
      new Proton.Velocity(
        new Proton.Span(4, 7),
        new Proton.Span(0, 360),
        "polar"
      )
    );
    emitter.addInitialize(
      new Proton.Position(new Proton.CircleZone(width / 2, height / 2, 100))

const color = this.getArrProp("color");
        const cross = this.getProp("cross", "dead");
        const random = this.getProp("random");
        const rotate = this.getArrProp("rotate");
        const g = this.getProp("g");
        const f = this.getArrProp("f");
        const emitterV = this.getProp("emitter");

        this.proton = new Proton();
        let emitter;
        if (emitterV === "follow") {
            emitter = new Proton.FollowEmitter();
        } else {
            emitter = new Proton.Emitter();
        }
        emitter.rate = new Proton.Rate(num, rps);

        emitter.addInitialize(new Proton.Mass(mass));
        emitter.addInitialize(new Proton.Radius(radius));
        emitter.addInitialize(new Proton.Life(life));
        emitter.addInitialize(new Proton.Velocity(v, tha, "polar"));
        if (body) emitter.addInitialize(new Proton.Body(body));

        let pos;
        if (position === "all" || position === "screen") {
            pos = new Proton.Position(new Proton.RectZone(0, 0, canvas.width, canvas.height))
        } else if (typeof position === "object") {
            pos = new Proton.Position(new Proton.RectZone(position.x, position.y, position.width, position.height))
        } else {
            emitter.p.x = canvas.width / 2;
            emitter.p.y = canvas.height / 2;
        }

createProton(canvas, width, height) {
    this.proton = new Proton();
    const emitter = new Proton.Emitter();
    emitter.rate = new Proton.Rate(this.props.num ? this.props.num : 50);
    emitter.damping = 0;

    emitter.addInitialize(new Proton.Mass(1));
    emitter.addInitialize(new Proton.Radius(4, 70));
    emitter.addInitialize(
      new Proton.Velocity(new Proton.Span(2, 10), new Proton.Span(0), "polar")
    );
    emitter.addInitialize(
      new Proton.Position(
        new Proton.LineZone(0, canvas.height, canvas.width, canvas.height)
      )
    );

    const dis = 150;
    const crossZoneBehaviour = new Proton.CrossZone(
      new Proton.RectZone(

createProton(canvas, width, height) {
    this.proton = new Proton();

    const emitter = new Proton.Emitter();
    emitter.rate = new Proton.Rate(
      new Proton.Span(100),
      new Proton.Span(0.05, 0.2)
    );

    emitter.addInitialize(new Proton.Mass(1));
    emitter.addInitialize(new Proton.Radius(1, 4));
    emitter.addInitialize(new Proton.Life(Infinity));

    const pointZone = new Proton.Position(
      new Proton.RectZone(0, 0, width, height)
    );
    emitter.addInitialize(pointZone);
    emitter.addInitialize(
      new Proton.Velocity(
        new Proton.Span(0.3, 0.6),
        new Proton.Span(0, 360),

createMiniEmitter(canvas) {
    const miniEmitter = new Proton.Emitter();
    miniEmitter.rate = new Proton.Rate(
      new Proton.Span(3, 6),
      new Proton.Span(1, 2)
    );

    miniEmitter.addInitialize(new Proton.Mass(1));
    miniEmitter.radiusInitialize = new Proton.Radius();
    miniEmitter.addInitialize(miniEmitter.radiusInitialize);
    miniEmitter.addInitialize(new Proton.Life(0.5, 1));
    miniEmitter.addInitialize(
      new Proton.V(
        new Proton.Span(1.5, 3),
        new Proton.Span(0, 70, true),
        "polar"
      )
    );

createProton(canvas, width, height) {
    this.proton = new Proton();

    const emitter = new Proton.Emitter();
    emitter.damping = 0.008;
    emitter.rate = new Proton.Rate(this.props.num ? this.props.num : 250);
    emitter.addInitialize(new Proton.Mass(1));
    emitter.addInitialize(new Proton.Radius(4));
    emitter.addInitialize(
      new Proton.Velocity(
        new Proton.Span(1.5),
        new Proton.Span(0, 360),
        "polar"
      )
    );
    const mouseObj = {
      x: width / 2,
      y: height / 2
    };

    const attractionBehaviour = new Proton.Attraction(mouseObj, 0, 0);
    const crossZoneBehaviour = new Proton.CrossZone(