http2human

http2human tries to translate http errors for human use. It wraps fetch promises and returns standardized errors.

When a request to your server from a device actually succeeds, it's nothing short of a small miracle. When it doesn't, a generic error message is dehumanizing to the person attempting to use your service.

Minimal example:

http2human('https://google.com').then(function(body) {
  // do something with your successful response.
  // `body` will be an object if it's JSON parsable,
  // otherwise it'll be a string
}).catch(function(err) {
  alert(err.suggestion);
})

Maximal example:

http2human('https://mycoolserver.com/login', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: { username: 'neil', password: 'nope' }
}).then(function(bodyObjectOrString) {
  // do something with your successful response
}).catch(function(err) {
  switch(err.name) {
   case 'NetworkError':
     console.error(err, err.stack);
     return alert("You might not be connected to the internet. Please check your connection and try again.");
   case 'ServerError':
     console.error(err, err.stack);
     if( err.suggestion ) { return alert(suggestion); }
     if( err.statusCode == 504 ) { return alert("Sorry, our server is backed up. Please try again later."); }
     if( err.responseBody ) { console.error(err.responseBody); }
     return alert("Sorry, something went wrong on our end. Please try again or email [email protected].");
   case 'UserError':
     if( err.suggestion ) { return alert(suggestion); }
     if( err.statusCode == 403 ) { return alert("Your username or password is incorrect") }
     if( err.responseBody && err.responseBody.retriesRemaining ) { return alert(`You have ${err.responseBody.retriesRemaining}`); }
     return alert("Hmm, something's wrong with your last request but we can't tell exactly what it is. Please check your information and try resubmitting or email [email protected]")
   case 'LowLevelError':
   default:
     return alert("Whoa, something went wrong that should not have gone wrong. Please let us know what happened at [email protected]")
  }
})

http2human will not work with all APIs. it assumes:

1. API responses are in JSON or plaintext
2. 5xx responses strictly indicate an unexpected server side error.
3. 4xx responses strictly indicate a user error that should be resolvable by the human on the other side.

In order to populate err.suggestion, the format of an error message suggesting foo must be one of the following:

{
  "error": {
    "message": "foo"
  }
}

{
  "message": "foo"
}

{
  "error": "foo"
}

foo

fetch is a new standard available in modern browsers and react native. If fetch is not available in your environment, http2human will use https://github.com/bitinn/node-fetch