Simple Complex number lib

complex.js

function Complex(re, im) {
  this.re = re;
  this.im = im;
  return this;
}

Complex.of = function (r, i) {
  return new Complex(r,i);
}

Complex.re = function(complex) {
  return complex.re;
}

Complex.im = function(complex) {
  return complex.im;
}

Complex.magnitude = function(complex) {
  return Math.sqrt(complex.re * complex.re + complex.im * complex.im);
}

Complex.argument = function(complex) {
  if (complex.re > 0 || complex.im !== 0) {
    return 2 * Math.atan(complex.im/(Math.sqrt(complex.re*complex.re + complex.im*complex.im) + complex.im))
  }
  
  if (compex.re < 0 && complex.im === 0) {
    return Math.pi;
  }
  
  if (x === 0 && y === 0) {
    return undefined;
  }
}

Complex.prototype.add = function(oc) {
  return Complex.of(this.re + oc.re, this.im + oc.im)
}

Complex.prototype.substract = function(oc) {
  return Complex.of(this.re - oc.re, this.im - oc.im)
}

//xu - yv , xv + yu
Complex.prototype.multiply = function(oc) {
  return Complex.of(this.re*oc.re - this.im*oc.im, this.im*oc.re + this.re*oc.im)
}

Complex.prototype.div = function(oc) {
  const re = (this.re*om.re + this.im*om.im)/(this.re*this.re+this.im*this.im)
  const im = (this.re*om.re - this.im*om.im)/(this.re*this.re+this.im*this.im)
  return Complex.of(re, im)
}

Complex.prototype.map = function(fn) {
  return Complex.of(fn(this.re), fn(this.im));
}

Complex.prototype.chain = function(fn) {
  return fn(this.re, this.im)
}




const a = Complex.of(1,2).multiply(Complex.of(3,2)).add(Complex.of(4,4));
const b = a.chain((re, im) => Complex.of(re* 2, im)).map(a => a + 100);