代码抛出字符串而不是错误时发出警告

Question

Sometimes in JavaScript, people will write throw 'Something went wrong'; instead of throw Error('something went wrong');

The first example is totally valid JS, but is not ideal because strings don't have stack traces, but errors do. Can the Closure Compiler warn when code is throwing strings instead of throwing errors?

Answer 1

You can do this using a JS Conformance file. Full details are here , but essentially you create a file js_conformance.txt :

requirement: {
  type: BANNED_CODE_PATTERN
  error_message: 'The use of throw with a string is not allowed. Throw an Error object instead.'

  value: '/** @param {string|String} str */ function template(str) { throw str }'
}

and pass it to the compiler using --conformance_configs=js_conformance.txt

If there are a lot of existing throw 'string' s in your codebase, you can clean them up using RefasterJS .

This video is a nice intro to both the conformance checks and RefasterJS.