[cowboyd]

Motivation

route(), command(), and extend() relied on large overload towers that imposed arbitrary limits on otherwise composable definitions. Larger applications could exceed those limits, while adding more overloads made the public types brittle and expensive to maintain.

The replacement must preserve exact inference across static elements, reusable extensions, nested routes, and dynamic checkpoints without filling normal hovers with internal type machinery.

Approach

Treat definition construction as a small type-level interpreter. Each built-in combinator carries an operation describing how it changes the current route, and a variadic fold applies those operations from left to right. Static operations are accumulated in bounded groups and materialized as concrete route, model, child, and phase shapes, which keeps compiler work controlled and public hovers readable.

The runtime remains ordinary immutable function composition. Concrete user combinators compose without registration; only generic transformations whose output depends on their input require mark(), because TypeScript cannot otherwise apply that higher-order relationship. Tuple inputs retain exact inference, while widened arrays intentionally fall back to a conservative type instead of pretending to know their sequence.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/configliere@26

commit: 21e1d0b