src/plugins/webpackHotDevClient.js
function handleSuccess() {
  clearOutdatedErrors();
  destroyErrorOverlay();

  var isHotUpdate = !isFirstCompilation;
  isFirstCompilation = false;
  hasCompileErrors = false;

  // Attempt to apply hot updates or reload.
  if (isHotUpdate) {
    tryApplyUpdates();
  }
}
function handleSuccess() {
  clearOutdatedErrors();
  destroyErrorOverlay();

  var isHotUpdate = !isFirstCompilation;
  isFirstCompilation = false;
  hasCompileErrors = false;

  // Attempt to apply hot updates or reload.
  if (isHotUpdate) {
    tryApplyUpdates();
  }
}
Successful compilation.