Middleware: WithFeatureFlagConfig

Per-instance configuration the consumer passes to withFeatureFlag(config, handler).

Keep this surface small — every field becomes part of the public API.

Parameters

• name

  (Required)

  Human-readable name for the flag. Echoed back on `ctx.featureFlag.name` and the default rejection body.

• evaluate

  (Required)

  Decide whether the flag is enabled for this request. Return `true`/`false` for a simple on-off check, or a FeatureFlagVerdict to also record a variant or provider payload. Async is fine. `ctx` carries the contributions of every upstream entry, so a flag placed after an auth middleware can target the verified caller. It is typed as BaseContext because this middleware declares no prerequisites and composes at any position; narrow it to the shape of the entries you place before it.

• rejectStatus

  (Optional)

  HTTP status when the flag rejects. Default is 404 — "this feature doesn't exist for you yet" — a softer reveal than 403 that avoids tipping off attackers about the existence of gated functionality.

• rejectBody

  (Optional)

  Body when the flag rejects.