Try-catch for synchronous errors in Node.js - Mini Project: Build & Apply

Try-catch for synchronous errors in Node.js

📖 Scenario: You are building a simple Node.js script that processes user input. Sometimes, the input might cause errors. You want to safely handle these errors so your program does not crash.

🎯 Goal: Build a Node.js script that uses try-catch to handle synchronous errors when parsing JSON input.

📋 What You'll Learn

Create a variable with a JSON string

Create a variable to hold the parsed object

Use try-catch to parse the JSON string safely

In the catch block, assign an error message to the parsed object variable

💡 Why This Matters

🌍 Real World

Handling user input or external data safely is important to avoid crashes in Node.js applications.

💼 Career

Error handling with try-catch is a fundamental skill for backend developers working with Node.js to build robust applications.

1

Create a JSON string variable

Create a variable called jsonString and set it to the string '{"name": "Alice", "age": 30}'.

Node.js

// Create a variable called jsonString with the exact JSON string
// Your code here

Need a hint?

Remember to use single quotes around the whole string and double quotes inside for JSON keys and values.

2

Create a variable to hold parsed data

Create a variable called parsedData and set it to null.

Node.js

const jsonString = '{"name": "Alice", "age": 30}';
// Create a variable called parsedData and set it to null
// Your code here

Need a hint?

Use let because we will change this variable later.

3

Use try-catch to parse JSON safely

Write a try-catch block. Inside try, parse jsonString using JSON.parse and assign it to parsedData. In catch, assign the string 'Error parsing JSON' to parsedData.

Node.js

const jsonString = '{"name": "Alice", "age": 30}';
let parsedData = null;
// Use try-catch to parse jsonString safely
// Your code here

Need a hint?

Use try { ... } catch (error) { ... } syntax and assign inside each block as instructed.

4

Complete the script with a safe JSON parse

Ensure the full script includes the jsonString variable, the parsedData variable initialized to null, and the try-catch block that parses jsonString safely and assigns the result or error message to parsedData.

Node.js

const jsonString = '{"name": "Alice", "age": 30}';
let parsedData = null;
try {
    parsedData = JSON.parse(jsonString);
} catch (error) {
    parsedData = 'Error parsing JSON';
}
// Finalize the script structure
// Your code here

Need a hint?

Make sure all parts are included exactly as before to complete the script.