Express Utils

A tiny utility package that makes Express route handlers cleaner by providing:

• TryCatch – Automatically catches async errors and sends JSON responses.
• SErr – A simple custom error class for returning HTTP status codes.

Installation

npm install express-try-catch

Features

• No repetitive try...catch blocks
• Simple custom HTTP errors
• Automatic JSON error responses
• Request logging after every request

Usage

Basic Example

Instead of writing this:

app.get("/users/:id", async (req, res) => {
  try {
    const user = await db.users.findById(req.params.id);

    if (!user) {
      return res.status(404).json({
        error: "User not found",
      });
    }

    res.json(user);
  } catch (err) {
    res.status(500).json({
      error: "Internal Server Error",
    });
  }
});

You can simply write:

import { TryCatch, SErr } from "express-try-catch";

app.get(
  "/users/:id",
  TryCatch(async (req, res) => {
    const user = await db.users.findById(req.params.id);

    if (!user) {
      throw new SErr("User not found", 404);
    }

    res.json(user);
  }),
);

Throwing Custom Errors

Use SErr whenever you want to return a specific HTTP status.

throw new SErr("Unauthorized", 401);

throw new SErr("Forbidden", 403);

throw new SErr("User not found", 404);

throw new SErr("Validation failed", 400);

If any other error is thrown, a 500 Internal Server Error response is returned automatically.

Returned Error Format

Errors are returned as JSON:

{
  "error": "User not found"
}

Logging

After every request, a log is printed in the following format:

[GET] /users/1 - 200 OK

Example:

[POST] /login - 401 Unauthorized

API

TryCatch(handler)

Wraps an async Express route handler.

Parameters

TryCatch(
  handler: (
    req: Request,
    res: Response,
    next: NextFunction
  ) => Promise<unknown>
)

Example

app.post(
  "/login",
  TryCatch(async (req, res) => {
    const user = await authenticate(req.body);

    if (!user) {
      throw new SErr("Invalid credentials", 401);
    }

    res.json(user);
  }),
);

SErr

A custom error class with an HTTP status code.

Constructor

new SErr(message, status);

Parameters

| Parameter | Type | Description | | --------- | -------- | ---------------- | | message | string | Error message | | status | number | HTTP status code |

Example:

throw new SErr("Email already exists", 409);

Example

import express from "express";
import { TryCatch, SErr } from "express-try-catch";

const app = express();

app.get(
  "/hello",
  TryCatch(async (req, res) => {
    res.json({
      message: "Hello World",
    });
  }),
);

app.get(
  "/error",
  TryCatch(async () => {
    throw new SErr("Something went wrong", 400);
  }),
);

app.listen(3000);