Composable Middleware Builder

app-builder is a JavaScript library for creating robust and composable asynchronous middleware pipelines, following the 'onion' model commonly seen in frameworks like Koa. It leverages Promises to enable clear and sequential execution of middleware functions, each capable of performing operations before and after subsequent middleware in the stack. The current stable version is 7.0.4. While a specific release cadence isn't explicitly stated, the active GitHub repository suggests ongoing maintenance. Its key differentiator lies in its simplicity and functional approach to middleware composition, providing a lightweight alternative to larger frameworks for building request-response flows or general data processing pipelines. It ships with TypeScript types, ensuring a better developer experience in TypeScript projects.