code: function createCountUp() {
      establishOptionsFromInputs();
      demo = new CountUp('myTargetElement', endVal, options);
      if (!demo.error) {
        errorSection.style.display = 'none';
        if (input('useOnComplete').checked) {
          demo.start(methodToCallOnComplete);
        }
        else {
          demo.start();
        }
        updateCodeVisualizer();
      }
      else {
        errorSection.style.display = 'block';
        document.getElementById('error').innerHTML = demo.error;
        console.error(demo.error);
      }
    }
docs: COUNTUP AND CODE VISUALIZER