typescript 45 lines · 6 steps

Catch-all routes and error shaping in NestJS

A wildcard controller turns unmatched routes into 404s, and an exception filter renders every HttpException as consistent JSON.

Explained by highlit
NestJS Intermediate exception-handling routing middleware error-formatting
1import {
2 Controller,
3 All,
4 Req,
5 NotFoundException,
6 HttpException,
7 ExceptionFilter,
8 Catch,
9 ArgumentsHost,
10 HttpStatus,
11} from '@nestjs/common';
12import { Request, Response } from 'express';
13 
14@Controller('*')
15export class NotFoundController {
16 @All()
17 handleUnknownRoute(@Req() req: Request): never {
18 throw new NotFoundException(
19 `Cannot ${req.method} ${req.originalUrl}`,
20 );
21 }
22}
23 
24@Catch(HttpException)
25export class HttpExceptionFilter implements ExceptionFilter {
26 catch(exception: HttpException, host: ArgumentsHost) {
27 const ctx = host.switchToHttp();
28 const res = ctx.getResponse<Response>();
29 const req = ctx.getRequest<Request>();
30 const status = exception.getStatus();
31 const payload = exception.getResponse();
32 
33 res.status(status).json({
34 statusCode: status,
35 error: HttpStatus[status] ?? 'Error',
36 message:
37 typeof payload === 'string'
38 ? payload
39 : (payload as { message?: string | string[] }).message ??
40 exception.message,
41 path: req.originalUrl,
42 timestamp: new Date().toISOString(),
43 });
44 }
45}
01 / 01
STEP 01

Walkthrough

Space play ←→ step click any line
Three takeaways
  1. 1A wildcard @Controller('*') gives you a single place to reject every route your app doesn't explicitly handle.
  2. 2An ExceptionFilter lets you intercept thrown exceptions and control the exact response body clients receive.
  3. 3Normalizing error payloads to a fixed shape makes APIs predictable for the clients that consume them.

Related explainers

typescript 
import { Controller, Param, Sse, MessageEvent } from '@nestjs/common';
import { Observable, interval, merge } from 'rxjs';
import { filter, map, takeWhile } from 'rxjs/operators';
import { JobService } from './job.service';

Streaming job progress with SSE in NestJS

server-sent-events reactive-streams rxjs
Intermediate 8 steps
java 
@RestController
@RequestMapping("/api/products")
@RequiredArgsConstructor
public class ProductBatchController {

Batch JSON Merge Patch in Spring

json-merge-patch rest-api partial-update
Intermediate 8 steps
typescript 
import {
  ArgumentsHost,
  Catch,
  ConflictException,

Turning TypeORM lock errors into 409s in NestJS

exception-handling optimistic-locking http-status
Intermediate 6 steps
java 
public class TimedFetchService {
 
    private final ExecutorService executor = Executors.newFixedThreadPool(8);
    private final HttpClient httpClient = HttpClient.newHttpClient();

Enforcing HTTP timeouts with a Future

concurrency timeouts thread-pool
Intermediate 8 steps
typescript 
import { Component } from '@angular/core';
import { RouterLink, RouterLinkActive } from '@angular/router';
import { NgFor } from '@angular/common';
 

Building an active-route navbar in Angular

routing standalone-components accessibility
Intermediate 6 steps
go 
package middleware
 
import (
	"net/http"

Role-based access control middleware in Gin

middleware authorization closures
Intermediate 7 steps

Share this explainer

Here's the card — post it anywhere.

Catch-all routes and error shaping in NestJS — share card
Made with highlit — turn any snippet into a walkthrough like this in about a minute.
Explain your code