Node.js Try-Catch Examples for Exception Handling

Introduction to Node.js Try-Catch

In the world of Node.js, exception handling is a crucial skill for developers. Using try-catch blocks allows you to gracefully handle errors that may occur during the execution of your code. This not only improves the reliability of your applications but also enhances the user experience by providing meaningful error messages. Below are three practical examples of Node.js try-catch usage, demonstrating how to manage exceptions in different contexts.

Example 1: Reading a File with Error Handling

Context

When working with file systems in Node.js, errors can occur if a file does not exist or if there are permission issues. This example demonstrates how to use a try-catch block when reading a file asynchronously.

const fs = require('fs');

function readFile(filePath) {
    try {
        const data = fs.readFileSync(filePath, 'utf8');
        console.log(data);
    } catch (error) {
        console.error(`Error reading file: ${error.message}`);
    }
}

readFile('nonexistent-file.txt'); // This will trigger the catch block

Notes

• The readFileSync method is used here for simplicity, but in a production environment, prefer asynchronous methods like fs.readFile to avoid blocking the event loop.
• Always log the error message to help with debugging.

Example 2: Handling API Requests with Async/Await

Context

In modern Node.js applications, you often interact with APIs. This example shows how to manage errors when making an HTTP request using async/await combined with a try-catch block.

const axios = require('axios');

async function fetchData(url) {
    try {
        const response = await axios.get(url);
        console.log(response.data);
    } catch (error) {
        console.error(`Error fetching data: ${error.message}`);
    }
}

fetchData('https://api.example.com/data'); // Handle potential network errors

Notes

• Axios is a popular library for making HTTP requests in Node.js. Make sure to install it using npm install axios.
• Consider handling specific error types, such as network errors or 404 responses, for more granular error reporting.

Example 3: Validating User Input

Context

When processing user input, it’s essential to validate the data before performing operations. This example demonstrates how to use try-catch for validating JSON input in a Node.js application.

``javascript function validateUserInput(input) { try { const user = JSON.parse(input); if (!user.name || !user.age) { throw new Error('Missing required fields: name and age must be provided.'); } console.log('User input is valid:', user); } catch (error) { console.error(Validation error: ${error.message}`);
}
}

validateUserInput(’{