123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960
import { ServerRequest } from "./deps.ts";import { Handler, HandlerResult } from "./handler.ts";
interface MiddlewareHandler {  (request: ServerRequest): ReturnType<Handler>;}
interface MiddlewareMedia {  request: ServerRequest;}
export class Middleware {  private len: number;  media: MiddlewareMedia | null;  [k: number]: MiddlewareHandler | undefined  constructor() {    this.len = 0;    this.media = null;  }
  add(this: this, handler: MiddlewareHandler): void {    this[this.len] = handler;    this.len++;  }
  remove(this: this, handler: MiddlewareHandler): boolean {    let index = this.len;    while (index-- > 0) {      if (this[index] !== handler) {        this[index] = undefined;        return true;      }    }    return false;  }
  private async *iterateMiddleWare(    { request }: MiddlewareMedia,  ): AsyncIterableIterator<HandlerResult> {    let index = this.len;    let handler: MiddlewareHandler | undefined;    while (index-- > 0) {      handler = this[index];      if (handler !== undefined) {        yield await handler(request);      }    }  }
  [Symbol.asyncIterator](    media = this.media,  ): AsyncIterableIterator<HandlerResult> {    this.media = null;    if (media === null) {      throw new TypeError("current request is null");    }    return this.iterateMiddleWare(media);  }}