message: Create new array if parsed babel file does not have the plugin section.
diff: @@ -51,7 +51,7 @@ const babylonParser = (file: string) => {
  const babelRC = getBabelRC(file, {useCache: true});
  const babel = JSON.parse(babelRC);
  - const plugins = babel.plugins.concat(['flow']);
  + const plugins = Array.isArray(babel.plugins) ? babel.plugins.concat(['flow']) : ['flow'];
  const config = {plugins, sourceType: 'module'};
  const ast = babylon.parse(data, config);
  