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import { GemContext } from './context.ts';
export type GemMiddleware = (ctx: GemContext, next: () => Promise<unknown>) => unknown | Promise<unknown>;
/** Compose multiple middleware functions into a single middleware function. */export function compose(    middleware: GemMiddleware[],): (context: GemContext, next?: () => Promise<unknown>) => Promise<unknown> {
    return function composedMiddleware(        context: GemContext,        next?: () => Promise<unknown>,    ): Promise<unknown> {        let index = -1;
        async function dispatch(i: number): Promise<void> {            if (i <= index) {                throw new Error("next() called multiple times.");            }            index = i;            let fn: GemMiddleware | undefined = middleware[i];            if (i === middleware.length) {                fn = next;            }            if (!fn) {                return;            }            await fn(context, dispatch.bind(null, i + 1));        }
        return dispatch(0);    };
}