(NextJS) Middleware Wrappers

For the common use case of wrapping a NextJS endpoint with methods that act as middleware.

Wraps a function in layers of other functions, while preserving the input/output type. The output of wrappers will always have the type of its last parameter (the wrapped function)

This function turns this type of composition...

withDatabase(
  logger.withContext("somecontext")(async (a, b) => {
    return a
  })
)

Into...

wrappers(withDatabase, logger.withContext("somecontext"), async (a, b) => {
  return a
})

Having this as a utility method helps preserve types, which otherwise can get messed up by the middlewares. It also can make the code cleaner where there are multiple wrappers.

EXAMPLES

In the context of request middleware you might write something like this...

const withRequestLoggingMiddleware = (next) => async (req, res) => {
  console.log(`GOT REQUEST ${req.method} ${req.path}`)
  return next(req, res)
}

Here's an example of a wrapper that takes some parameters...

const withLoggedArguments =
  (logPrefix: string) =>
  (next) =>
  async (...funcArgs) => {
    console.log(logPrefix, ...funcArgs)
    return next(...funcArgs)
  }

Installation

Automatic Deploy to NPM

To have your PR be automatically deployed to NPM, make sure to tag your commit messages with the Angular JS commit message format.

i.e. | Commit message | Release type | | -------------- | ------------ | | fix(pencil): stop graphite breaking when too much pressure applied | Fix Release | | feat(pencil): add 'graphiteWidth' option | Feature Release | | perf(pencil): remove graphiteWidth option | BREAKING CHANGE: The graphiteWidth option has been removed. The default graphite width of 10mm is always used for performance reasons. | Breaking Release (Note that the BREAKING CHANGE: token must be in the footer of the commit) |