Improved Node.js compatibility for Edge Middleware and Edge Functions

This changelog entry is historical. Edge Functions are deprecated for new projects. Use with the Node.js runtime and . Use for request-time routing before a response completes.Note:Vercel FunctionsFluid computeRouting Middleware

Vercel and now support more Node.js modules. You may want to make use of these modules directly, but many of these low-level are pieces of core functionality that other modules depend on. Adding support for these APIs expands the compatibility of existing npm packages.Routing MiddlewareEdge FunctionsAPIs

The following APIs are now supported:

You can take advantage of these additional APIs in Routing Middleware and Edge Functions with your next deployment. For current projects, use with the Node.js runtime by default. Existing Edge Runtime projects can use the .Vercel FunctionsEdge Runtime reference

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• **AsyncLocalStorage: **Support for maintaining data for an invocation between different asynchronous execution contexts, which allows you to pass state to the context even when the function is hot and module context is preserved.

• **EventEmitter: **API to build event-driven systems that serves as a core building block for communication between libraries that control I/O and listeners that process data when events occur.A flexible

• **Buffer: **The most common way of handling binary data in Node.js, available globally or importable from .buffer

• **assert: **A set of assertion functions to validate invariants and logical rules that are very useful to explicitly test assumptions in your code path that need to run in Edge Functions.

• and **util.callbackify: **A helper function to convert a callback-style function signature into one that returns a , and a helper function to convert a function that returns a into one that accepts a callback.util.promisifyPromisePromise

• **util.types: **A set of functions to validate that objects are of a given type.