[fix] When I use multiple routing instances and the request method is incorrect(Define post but use get), the error message is "undefined is not an object (evaluating 'route.methods.length'"

[zhaoyuqiqi]

Describe the bug

Node.js version: 20.11.1

OS version: MacBook Pro macOS 14.1.2

Description: When I use multiple routing instances and the request method is incorrect(Define post but use get), the error message is "undefined is not an object (evaluating 'route.methods.length'"

Actual behavior

throw an error

Expected behavior

No-throw error

Code to reproduce

import Koa from 'koa';
import KoaRouter from '@koa/router';

const app = new Koa();
const userRouter = new KoaRouter();
userRouter.prefix('/user');
userRouter.post('/login', (ctx, next) => {
  ctx.body = 'login success';
});
const teamRouter = new KoaRouter();
teamRouter.prefix('/team');
teamRouter.post('/test', (ctx, next) => {
  ctx.body = 'test success';
});

app.use(userRouter.routes());
app.use(
  userRouter.allowedMethods({
    throw: true,
    notImplemented: () => new Error('notImplemented'),
    methodNotAllowed: () => new Error('methodNotAllowed')
  })
);
app.use(teamRouter.routes());
app.use(
  teamRouter.allowedMethods({
    throw: true,
    notImplemented: () => new Error('notImplemented'),
    methodNotAllowed: () => new Error('methodNotAllowed')
  })
);

app.listen(8000, () => {
  console.log('success');
});

Checklist

• [x] I have searched through GitHub issues for similar issues.
• [x] I have completely read through the README and documentation.
• [x] I have tested my code with the latest version of Node.js and this package and confirmed it is still not working.

[zhaoyuqiqi]

Define post method but throw an error when I use get method to request