TECH_README.txt

READ FIRST OF ALL
1) I don't know why, but 'tslib' in es5 compilation uses constructions like this:
    d.__proto__ = b;
        or 
    Object.setPrototypeOf

to support records like 
    class A extends B { ... }

It is the terrible shit because of this: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/setPrototypeOf
There is a warning about not to use it. 
In future I'll try to replace it with something more correct.

2) Window location and absolute references
    window.addEventListener('hashchange', (e) => {console.log(location.hash)})
    goog.global.location.origin + goog.global.location.pathname + goog.global.location.search
    https://stackoverflow.com/questions/6390341/how-to-detect-url-change-in-javascript

3) Pay attention to document.querySelectAll
    https://stackoverflow.com/questions/16791527/can-i-use-a-regular-expression-in-queryselectorall

    var dom = stage.domElement();
    console.log(dom);

    var selection1 = dom.querySelectorAll('[fill^="url("]');
    var selection2 = dom.querySelectorAll('[clip-path*="url("]'); //TODO find the difference between ^= and *=
    console.log(selection1);
    console.log(selection2);

4) Different DEFS + USE usage: http://tutorials.jenkov.com/svg/defs-element.html