How could I use the request or context in formatError()?

[jleeothon]

Hello! I'm migrating from express-graphql to graphql-http. The function customFormatErrorFn() from the former maps naturally to the latter's formatError(). However there are some differences in the codebase that I maintain, which make a direct migration a bit hard:

Before:

const middleware = graphqlHTTP(function (request, response, params) {
  return {
    customFormatErrorFn(error) {
      // I have access to request, response, params, including request.myContext
      request.context.logger.error("blabla");
    }
};

app.use('/some/path', middleware);

After:

const middleware = createHandler({
  formatError(error) {
    // Have access to error, but not to request or context
  }
});

app.use('/some/path', middleware);

In my specific use case, we're calling a logger as e.g. request.myContext.logger.info().

I'm trying to find a workaround with e.g. onSubscribe(), or by adding another middleware before or after, but haven't made it work yet.

Any support is appreciated! Thanks!

[enisdenjo]

At the moment, this syntax is not supported. This could be a good feature to add though.

However, you can achieve the same thing by using the createHandle IIFE style:

- const middleware = createHandler({
+ const middleware = (request, response, params) => createHandler({
  formatError(error) {
    // Have access to error and request or context
  }
- });
+ })(request, response, params);

app.use('/some/path', middleware);

Since the creation of the handler is a cheap operation, this should not cause any issues performance-wise.

[jleeothon]

Thank you. Will try this!