Type Alias Middleware<E, P, D>

Middleware: (
ctx: Context<E, P, D>,
next: () => Promise<Response>,
) => Promise<Response>

Middleware function type with next() pattern.

Middleware can:

Run code before calling next() (pre-processing)
Run code after calling next() (post-processing)
Short-circuit by returning a Response without calling next()
Throw HttpError to return an error response

Type Parameters

E = Env
Environment type
P = Params
Route parameters type
D = Record<string, any>
Data type for middleware-set data

Type Declaration

- (ctx: Context<E, P, D>, next: () => Promise<Response>): Promise<Response>
- Parameters
  - ctx: Context<E, P, D>
  - next: () => Promise<Response>
  Returns Promise<Response>

Example

const timingMiddleware: Middleware = async (ctx, next) => {
    const start = Date.now();

    const response = await next();

    ctx.log.info(`Request took ${Date.now() - start}ms`);
    return response;
};