message: Allow comments in extended tsconfig files
diff: @@ -77,7 +77,8 @@ export function getTSConfig(globals, collectCoverage: boolean = false) {
  if (typeof external.extends === 'string') {
  const parentConfigPath = path.join(path.dirname(configPath), external.extends);
  - config = Object.assign({}, require(parentConfigPath).compilerOptions, config);
  + const includedContent = fs.readFileSync(parentConfigPath, 'utf8');
  + config = Object.assign({}, tsconfig.parse(includedContent, parentConfigPath).compilerOptions, config);
  }
  }
  