code: function transformCode(transformFn, script) {
    let source;
    if (script.url != null) {
      source = script.url;
    } else {
      source = 'Inline Babel script';
      inlineScriptCount++;
      if (inlineScriptCount > 1) {
        source += ' (' + inlineScriptCount + ')';
      }
    }
  
    return transformFn(
      script.content,
      {
        filename: source,
        ...buildBabelOptions(script),
      }
    ).code;
  }
docs: Actually transform the code.