Functions

NEMO uses Next.js native middleware function schema to provide you with a familiar way of writing middleware functions and enabling you to use 3rd party packages without any issues.

Function schema

NEMO middleware function API is fully compatible with Next.js native API. It's just extending the event prop with some additional props and functions.

import { NextMiddleware } from "@rescale/nemo";
 
const example: NextMiddleware = async (request, event) => {
  // function body
};

Explanation

Prop:  request

Type: NextRequest

That's a user middleware's request passed to middleware and can be later updated by functions in chain.

This props cookies will only deffer from the original user's request if you've forwarded any response it in the chain.

Prop:  event

Type: NemoEvent extends NextFetchEvent

This property contains event object for serverless functions execution extended via nemo prop which contains chain execution storage.

Logger methods

The event object includes built-in logging capabilities that use the same logger as NEMO internally:

// Debug logging (only displayed when debug is enabled in config)
event.log("Processing user request", userId);
 
// Error logging (always displayed)
event.error("Failed to process request", error);
 
// Warning logging (always displayed)
event.warn("Deprecated feature used", featureName);

These logger methods maintain the "[NEMO]" prefix for consistent logging throughout your middleware chain.