Chapter quiz · Routing

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8 questions on Routing. Pass 70% to clear the chapter.

Quiz

Routing — Chapter Quiz

Eight questions on @koa/router, ctx.params, ctx.query, router.routes()/allowedMethods(), prefix, per-route middleware, redirect, and 404 fallthrough.

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Question 1
1
Koa has no built-in router. Which package is the de-facto standard router maintained by the Koa team?
Akoa-routeB@koa/routerCkoa-express-routerDkoa-path
@koa/router (formerly koa-router) is the official maintained package. It supports named routes, URL params, prefix, per-route middleware, and nested routers.
Question 2
2
How do you read the :id segment from the URL /users/42 with @koa/router?
Actx.request.params.idBctx.params.idCctx.query.idDctx.state.params.id
@koa/router populates ctx.params with named URL segments. ctx.query holds parsed query-string values, not path params.
Question 3
3
Why should you always call both router.routes() and router.allowedMethods() on app.use?
Aroutes() registers handlers; allowedMethods() auto-responds with 405 / 501 for unsupported methodsBallowedMethods() is required to parse URL paramsCThey must be called in the same app.use call or routing breaksDroutes() alone causes a memory leak
router.routes() dispatches matched routes. router.allowedMethods() adds automatic 405 Method Not Allowed and 501 Not Implemented responses, which is required for proper REST compliance.
Question 4
4
How do you group all routes in a router under the /api/v1 prefix?
Arouter.prefix(\"/api/v1\")Brouter.base(\"/api/v1\")Capp.use(\"/api/v1\", router.routes())Drouter.namespace(\"/api/v1\")
router.prefix('/api/v1') prepends the string to every route registered on that router instance. It can be called before or after route definitions.
Question 5
5
Which code correctly issues a 301 permanent redirect to /new-path in @koa/router?
Actx.redirect(\"/new-path\"); ctx.status = 301Bctx.redirect(\"/new-path\")Cctx.response.redirect(301, \"/new-path\")Drouter.redirect(\"/old\", \"/new-path\", 302)
ctx.redirect(url) sets the Location header and defaults to 302. Override with ctx.status = 301 afterwards (or before) to make it permanent. router.redirect() also works but defaults to 301 and is route-level.
Question 6
6
Per-route middleware in @koa/router runs before the route handler and must call await next() to reach it.
TTrueFFalse
You can pass any number of middleware functions before the final handler: router.get('/path', authMiddleware, handler). Each must await next() to pass control to the next function.
Question 7
7
Access parsed query-string parameters (e.g. ?page=2) via ctx.___.
ctx.query is an object of key-value pairs parsed from the URL query string. It is a shortcut for ctx.request.query. Values are always strings.
Question 8
8
Which strategies handle unmatched routes (404) correctly in a Koa app using @koa/router?
Select all that apply.
AAdd a catch-all app.use after router.routes() that sets ctx.status = 404BRegister a router.all(\"(.*)\" route at the end that sets ctx.status = 404CDo nothing — Koa automatically sends 404 for unmatched routesDCheck ctx.status === 404 in a downstream middleware after await next()
Koa sets ctx.status = 404 by default when no middleware sets a body, but you need explicit handling for a proper JSON error response. A catch-all middleware or route, or checking status after await next(), are all valid patterns.