Question - Composing multiple middleware

I’m trying to expose a wrapper function so that all my lambda handlers have the same middleware applied to them.

const wrapper = (handler) =>
  compose(
    // add cors headers last so even error responses from the
    // errorHandler middleware have cors headers applied
    cors(),
    errorHandler(),
    jsonSerializer(),
    classValidator(),
  )(handler)

However I’m struggling to get the type information to line up.

Is it possible to chain these middlewares like this as you can do using middy?

[dbartholomae]

That’s the same problem - unfortunately currently not fully solvable in TypeScript. I would recommend going with the solution where the handler is wrapped for now until TypeScript has better inference for generics.

[dbartholomae]

Thanks, I’ll adapt it so it also work in strict mode next week 😃