url.join like function for the browser

url-join.js

function urlJoin(/* components */) {
  const components = Array.prototype.slice.call(arguments);
  let queryParamsReached = false;
  function urlComponentsReducer(accumulator, currentComponent, currentIndex) {
    if (currentComponent instanceof Array) {
      return accumulator + (queryParamsReached ? '' : '/') + currentComponent.reduce(urlComponentsReducer);
    }
    let modifiableComponent = currentComponent;
    if (!queryParamsReached && currentComponent.indexOf('?') > -1) {
      queryParamsReached = true;
    }
    if (currentComponent[currentComponent.length - 1] === '/') {
      modifiableComponent = currentComponent.slice(0, -1);
    }
    if (currentIndex > 0 && currentComponent[0] !== '/' && !queryParamsReached) {
      modifiableComponent = '/' + currentComponent;
    } else if (currentIndex === 0 && currentComponent[0] === '/' && currentComponent[1] === '/' && typeof window !== 'undefined' && window.location && window.location.protocol) {
      modifiableComponent = window.location.protocol + currentComponent;
    }
    return accumulator + modifiableComponent;
  }
  return components.reduce(urlComponentsReducer, '').replace(/[?/]+$/, '');
}

urlJoin('//google.com', '/test/', '?','k=v') // https://google.com/test?k=v
urlJoin('//google.com', '/test/', '?','') // https://google.com/test
urlJoin('//google.com', '/test/', ['go', '/deeper/?']) // https://google.com/test/go/deeper
urlJoin('//google.com', '/test/', ['go', '/deeper/?', 'key=value']) // https://google.com/test/go/deeper/?key=value