Display the Error

Let’s consider the following code snippet:

Javascript

import { Request, Response } from 'express'; 
  
function getUserById(req: Request, res: Response) { 
    const userId = req.params.id; 
    const user = findUserById(userId); 
  
    if (!user) { 
        throw new Error('User not found!'); 
    } 
  
    res.json(user); 
} 
  
function findUserById(userId: string) { 
  
    // Logic to find the user by ID in the  
    // database ... 
  
    // Assume the user was not found 
    return null; 
}

In this code, we have an API endpoint getUserById that takes a request object (req) and a response object (res). It retrieves the user ID from the request parameters, calls a findUserById function to fetch the user data from the database, and throws a generic Error with the message “User not found!” if the user does not exist.

Output (Error):

Output

The error message in this case is generic and does not provide specific information about the encountered issue, which makes it challenging to determine whether the user ID was invalid or if there was an issue with the database.

TypeScript Custom Errors in RESTful API

In this article, we will explore the importance of using custom error handling in TypeScript for RESTful APIs. We will begin by highlighting the problem statement, followed by demonstrating the problem with code examples and error outputs. Finally, we will present a solution approach using custom error classes and showcase the desired output. By the end, you will have a clear understanding of how to implement custom errors to improve error handling in your TypeScript-based RESTful APIs.

Display the Error

Javascript

TypeScript Custom Errors in RESTful API

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