code: function headlessStep() {
        if (!cy._private.animationsRunning) {
          return;
        }
  
        requestAnimationFrame(function animationStep(now$$1) {
          stepAll(now$$1, cy);
          headlessStep();
        });
      }
docs: save cycles when no style used NB the animation loop will exec in headless environments if style enabled and explicit cy.destroy() is necessary to stop the loop