Generalized Mandelbrot in JavaScript

mandel.js

/** mandel5 */
// Uses DrCiRCUiT's Canvas Library, but you can change the drawing / canvas methods for something else.
(function () {
    var scr;
    var plane = {
        real: { min: -2, max: 2 },
        imag: { min: -2, max: 2 }
    };
    function setup() {
        scr = dcl.setupScreen(512, 512);
        scr.setBgColor('black');
        document.body.style.backgroundColor = 'black';
    }
    function scale(n, min, max, omin, omax){
        return n * (max - min) / (omax - omin) + min;
    }
    function complex(real, imag){
        let abs = Math.sqrt(real * real + imag * imag);
        return {
            r: real,
            i: imag,
            abs: abs,
            add: function(z){
                return complex(real + z.r, imag + z.i);
            },
            mul: function(z){
                let r = real * z.r + imag * z.i * -1;
                let i = real * z.i + imag * z.r;
                return complex(r,i);
            },
            pow: function(n){
                let abston = Math.pow(abs, n);
                let theta = Math.atan2(imag, real);
                let r = abston * Math.cos(theta * n);
                let i = abston * Math.sin(theta*n);
                return complex(r,i);
            }
        };
    }
    function mandel(c, maxItertions, escapeRadius, power){
        let z = complex(0,0);
        for(var i = 0;i<maxIterations;i++){
            z = z.pow(power).add(c);
            if(z.abs > escapeRadius){
                break;
            }
        }
        return {
            z: z,
            i: i
        }
    }
    function ship(c, maxItertions, escapeRadius, power){
        let z = complex(0,0);
        for(var i = 0;i<maxIterations;i++){
            z = complex(Math.abs(z.r), Math.abs(z.i));
            z = z.pow(power).add(c);
            if(z.abs > escapeRadius){
                break;
            }
        }
        return {
            z: z,
            i: i
        }
    }
    let maxIterations = 25;
    let escapeRadius = 2;
    let power = 3;
    function draw() {
        for (let x = 0; x < scr.width; x++) {
            for (let y = 0; y < scr.height; y++) {
                //Map x,y to complex real, imag
                let r = scale(x, plane.real.min, plane.real.max, 0, scr.width);
                let i = scale(y, plane.imag.min, plane.imag.max, 0, scr.height);
                //Make complex number
                let c = complex(r,i);
                //Run Mandelbrot
                let res = mandel(c, maxIterations, escapeRadius,power);
                //let res = ship(c, maxIterations, escapeRadius,power);
                //Check if diverged
                if(res.z.abs > escapeRadius){
                    let alpha = (res.i - Math.log(res.z.abs) / Math.log(2)) / maxIterations * 2;
                    dcl.rect(x,y,1,1,"rgba(255,0,0,"+alpha.toFixed(2)+")");
                }
                if(res.z.abs < escapeRadius){
                    let alpha = (res.z.abs - Math.log(res.z.abs) / Math.log(power)) / maxIterations *.2;
                    dcl.rect(x,y,1,1,"rgba(255,0,0,"+alpha.toFixed(2)+")");
                }
            }
        }
    }
    setup();
    draw();
})();