Fejl Error Utility

Fejl is a JavaScript and TypeScript utility library designed to streamline the creation and management of custom error classes in Node.js applications. Currently in its stable v4.0.1 release, Fejl offers a predictable release cadence with major versions typically introducing significant changes like ESM support or Node.js version bumps. Its core functionality revolves around `MakeErrorClass`, which allows developers to define custom error types with default messages and properties, drastically reducing boilerplate compared to native `Error` extension. Key differentiators include static `assert` and `makeAssert` methods for concise conditional error throwing, and a collection of pre-defined HTTP error classes. Fejl aims to improve code readability and maintainability by centralizing error definitions and providing convenient assertion patterns.