Helpers

handleCors

All-in-one helper. Appends the right CORS headers and, on a preflight request, returns a ready-to-send Response.

declare function handleCors(
    event: IAppEvent,
    options: Options,
): Response | undefined;

router.all('/', defineCoreHandler((event) => {
    const corsResponse = handleCors(event, { origin: '*' });
    if (corsResponse) {
        return corsResponse;
    }

    return 'ok';
}));

appendCorsHeaders

Appends the non-preflight CORS headers (Access-Control-Allow-Origin, Access-Control-Allow-Credentials, Access-Control-Expose-Headers).

declare function appendCorsHeaders(
    event: IAppEvent,
    options: Options,
): void;

appendCorsPreflightHeaders

Appends the preflight CORS headers (Access-Control-Allow-Methods, Access-Control-Allow-Headers, Access-Control-Max-Age, plus origin/credentials).

declare function appendCorsPreflightHeaders(
    event: IAppEvent,
    options: Options,
): void;

isPreflightRequest

Returns true for OPTIONS requests carrying both an Origin header and Access-Control-Request-Method.

declare function isPreflightRequest(event: IAppEvent): boolean;

isCorsOriginAllowed

Pure check against the origin option — useful when you need to make a CORS-related decision (e.g. logging, custom redirect) outside the plugin itself.

declare function isCorsOriginAllowed(
    origin: string | null | undefined,
    options: Options,
): boolean;