try..catch not catching async/await errors

问题

Perhaps I misunderstood how catching errors with async/await is supposed to work from things articles like this https://jakearchibald.com/2014/es7-async-functions/ and this http://pouchdb.com/2015/03/05/taming-the-async-beast-with-es7.html, but my catch block is not catching 400/500.

async () => {
  let response
  try {
   let response = await fetch('not-a-real-url')
  }
  catch (err) {
    // not jumping in here.
    console.log(err)
  }
}()

example on codepen if it helps

回答1:

400/500 is not an error, it's a response. You'd only get an exception (rejection) when there's a network problem.

When the server answers, you have to check whether it's good or not:

try {
    let response = await fetch('not-a-real-url')
    if (!response.ok) // or check for response.status
        throw new Error(response.statusText);
    let body = await response.text(); // or .json() or whatever
    // process body
} catch (err) {
    console.log(err)
}

来源：https://stackoverflow.com/questions/33355033/try-catch-not-catching-async-await-errors