Middleware: Middleware

The shape of a middleware produced by defineMiddleware.

Three call signatures:

• Handler (cascade) — mw(config, handler) (or mw(handler)) returns the produced fetch handler, with Base pushed inward from the contextual type of the call's return. Base is constrained to In & BaseContext for prerequisite enforcement, and the handler parameter is wrapped in NoConflict for collision detection — both surface at the call site.
• Handler (propagation) — the same call when the wrapped handler declares prerequisites this layer cannot meet from the inward push alone. Ctx is read outward off that handler and re-published as this layer's own requirement, minus the key it contributes.
• Config-only — mw(config) (or mw() for config-less) returns an Entry for use in a pipeline array.

The two directions cannot share one signature: the cascade needs the handler argument to be a dead inference site, and the propagation needs it to be the live one. Splitting them into ordered overloads lets each keep what it needs.

Parameters

• args

  (Required)