function getTranslation(transform) {

  // Create a dummy g for calculation purposes only. This will never

  // be appended to the DOM and will be discarded once this function

  // returns.

  var g = document.createElementNS("http://www.w3.org/2000/svg", "g");

  // Set the transform attribute to the provided string value.

  g.setAttributeNS(null, "transform", transform);

  // consolidate the SVGTransformList containing all transformations

  // to a single SVGTransform of type SVG_TRANSFORM_MATRIX and get

  // its SVGMatrix.

  var matrix = g.transform.baseVal.consolidate().matrix;

  // As per definition values e and f are the ones for the translation.

  return [matrix.e, matrix.f];

}

console.log(getTranslation("translate(20,30)"))  // simple case: should return [20,30]

console.log(getTranslation("rotate(45) skewX(20) translate(20,30) translate(-5,40)"))