polyfill.js

'use strict';
// Polyfills for (old) firefox 75
// From https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/
if (typeof Object.assign !== 'function') {
  Object.assign = function (target, varArgs) { // .length of function is 2
    if (target == null) { // TypeError if undefined or null
      throw new TypeError('Cannot convert undefined or null to object');
    }

    var to = Object(target);

    for (var index = 1; index < arguments.length; index++) {
      var nextSource = arguments[index];

      if (nextSource != null) { // Skip over if undefined or null
        for (var nextKey in nextSource) {
          // Avoid bugs when hasOwnProperty is shadowed
          if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
            to[nextKey] = nextSource[nextKey];
          }
        }
      }
    }
    return to;
  };
}

if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('service-worker.js');
}