How AsyncLocalStorage Solves Parameter Pollution in Node.js Backend Apps

A backend developer building a cloth rental booking app encountered a recurring problem where request data like orderId had to be manually passed through every function in the call chain, even those that didn't use it directly. This pattern, known as parameter pollution, led to tight coupling where adding a single new parameter required modifying multiple files across the codebase. Searching for a cleaner solution, the developer discovered AsyncLocalStorage, a Node.js feature from the async_hooks module that scopes storage to a specific async execution context. By storing request data once at the entry point, any function anywhere in the execution chain can access it directly without receiving it as a parameter. The approach requires just two utility functions — one to initialize the context at the request boundary and one to retrieve it from anywhere in the async call stack.