How to resolve KOA- next() is not a function error? - koa

Question

I have built a simple koa framework application.After adding routes am trying to hit the /health GET route. It throws the below error:
TypeError: next is not a function
at cookieParser (c:\Userxxs\x\gimt\dp-my-app\node_modules\cookie-parser\index.js:46:14)
at dispatch (c:\Users\B748806a\gimt\dp-my-app\node_modules\koa-compose\index.js:42:32)
at bodyParser (c:\Users\B748806a\gimt\dp-my-app\node_modules\koa-bodyparser\index.js:95:11)
at processTicksAndRejections (internal/process/task_queues.js:93:5)
Below are the files and their order of execution:
server.js
const app = require("./app.js");
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => console.log(`Listening on port: ${PORT}`));
app.js
"use strict";
const koa = require('koa');
const koaRouter = require('koa-router');
const app = new koa();
const router = new koaRouter();
const middleware = require("./src/main/middlewares/middlewares");
const routes = require("./src/main/middlewares/route-path");
const init = async () => {
try {
/**
* Step 2: load endpoint routes for the application
*/
routes(router)
} catch (err) {
logger.error({
err
});
}
};
/**
* Step 1: load middleware setup - cors,helmet from KP Spring cloud service
*/
middleware(app);
init();
module.exports = app
middleware.js
const koa = require("koa");
const koaRouter = require('koa-router');
const router = new koaRouter();
const cors = require("koa-cors");
const compression = require("koa-compress");
const helmet = require("koa-helmet");
const cookieParser = require("cookie-parser");
const bodyParser = require('koa-bodyparser')
const ActuatorRouter = require('pm-js-actuator').koa //internal library
const ACTUATOR_OPTIONS = {
health: {
enabled: true
},
livenessprobe: {
enabled: true
},
env: {
enabled: false
},
info: {
enabled: true,
secure: false
}
}
function middleware(app) {
// Use the CORS for the time being.
app.use(cors())
// Let's don the security helmet
app.use(helmet())
app.use(helmet.frameguard())
app.use(helmet.ieNoOpen())
app.use(helmet.frameguard({
action: 'sameorigin'
}))
app.use(helmet.noSniff())
app.use(helmet.referrerPolicy({
policy: 'same-origin'
}))
app.use(helmet.xssFilter())
//app.disable('x-powered-by')
app.use(ActuatorRouter.getRouter(ACTUATOR_OPTIONS).routes())
app.use(bodyParser())
app.use(cookieParser());
// Set up compression
app.use(compression());
}
module.exports = middleware;
route-path.js
const RootHeathController = require("../controller/root-health-controller")
const routes = (router) => {
router.get("/health", RootHeathController.handler)
};
module.exports = routes
root-health-controller.js
const handler = async (ctx, next) => {
ctx.body="Hi";
}
module.exports = {
handler
};
The application is started successfully on port 3000. But when i hit, /health from postman, it throws the mentioned error. Any solution?

Answer 1

The problem here is, that cookie-parser seems to be an express - thing (see also repo url: https://github.com/expressjs/cookie-parser). So to test this I created a minimal version of your code:
const koa = require('koa');
const koaRouter = require('koa-router');
const bodyParser = require('koa-bodyparser');
const cookieParser = require("cookie-parser");
const app = new koa();
app.use(bodyParser());
app.use(cookieParser()); // <-- comment this line
const router = new koaRouter();
router.get("/health", async (ctx, next) => {
ctx.body = 'hi';
});
app.use(router.routes());
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => console.log(`Listening on port: ${PORT}`));
Calling the localist:3000/health endpoint throws the same error. But if you comment the app.use(cookie-parser()) line all works fine.
The question is, why you would need this library? You should be able to set and get cookies in koa with ctx.cookies.get and ctx.cookies.set