Express router 404 Not Found - node.js

Question

I used express-generator and the following are app.js:
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var cors = require('cors');
var app = express();
app.use(cors());
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
app.use('/', indexRouter);
app.use('/users', usersRouter);
// catch 404 and forward to error handler
app.use(function (req, res, next) {
next(createError(404));
});
// error handler
app.use(function (err, req, res, next) {
// set locals, only providing error in development
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
// render the error page
res.status(err.status || 500);
res.render('error');
});
module.exports = app;
And when access to http://localhost:5000/api/ got Error:
Not Found
404
NotFoundError: Not Found
at D:\_projects\booking-system\api\app.js:28:8
at Layer.handle [as handle_request] (D:\_projects\booking-system\api\node_modules\express\lib\router\layer.js:95:5)
at trim_prefix (D:\_projects\booking-system\api\node_modules\express\lib\router\index.js:317:13)
at D:_projects\booking-system\api\node_modules\express\lib\router\index.js:284:7
at Function.process_params (D:_projects\booking-system\api\node_modules\express\lib\router\index.js:335:12)
at next (D:_projects\booking-system\api\node_modules\express\lib\router\index.js:275:10)
at D:_projects\booking-system\api\node_modules\express\lib\router\index.js:635:15
at next (D:_projects\booking-system\api\node_modules\express\lib\router\index.js:260:14)
at Function.handle (D:_projects\booking-system\api\node_modules\express\lib\router\index.js:174:3)
at router (D:_projects\booking-system\api\node_modules\express\lib\router\index.js:47:12)
Following is routes/index:
var express = require('express');
var router = express.Router();
/* GET home page. */
router.get('/', function(req, res, next) {
res.render('index', { title: 'API' });
});
module.exports = router;
Thank you very much for your helps !

Answer 1

The issue is that you define a GET / route in your routes/index.js file and then register it as app.use('/', indexRouter) in your app.js.
So you either change your routes/index.js file to it looks like this:
var express = require('express');
var router = express.Router();
// Note the /api
router.get('/api', function(req, res, next) {
res.render('index', { title: 'API' });
});
module.exports = router;
Or you keep routes/index as it is but your change the way your register it in your main.js to this:
// ...
// Note the /api
app.use('/api', indexRouter);
app.use('/users', usersRouter);
// ...