Error handling in JavaScript using try/catch

Error handling in JavaScript using try/catch

1. The Basics of try/catch

try/catch lets you handle errors gracefully instead of letting your program crash.

Syntax:

try {
    // Code that might throw an error
} catch (error) {
    // Code to handle the error
} finally {
    // Optional: code that runs regardless of error
}
  • try: The block where you place code that may fail.
  • catch: Runs if an error occurs in the try block. Receives an error object.
  • finally (optional): Runs always, whether an error occurred or not. Useful for cleanup.

2. Example: Basic try/catch

try {
    let result = riskyOperation(); // might throw an error
    console.log("Operation succeeded:", result);
} catch (error) {
    console.log("An error occurred:", error.message);
} finally {
    console.log("This runs no matter what.");
}

3. Throwing Your Own Errors

You can use throw to raise a custom error:

function divide(a, b) {
    if (b === 0) {
        throw new Error("Cannot divide by zero!");
    }
    return a / b;
}

try {
    console.log(divide(10, 0));
} catch (error) {
    console.log("Error:", error.message);
}

Output:

Error: Cannot divide by zero!

4. Catching Specific Errors

You can check the type or message of the error inside catch:

try {
    JSON.parse("invalid json");
} catch (error) {
    if (error instanceof SyntaxError) {
        console.log("JSON syntax error!");
    } else {
        console.log("Some other error:", error.message);
    }
}

5. Best Practices

  1. Only wrap risky code in try/catch to avoid hiding bugs.
  2. Log or handle errors properly, don’t silently ignore them.
  3. Use finally for cleanup, e.g., closing a file, stopping a loader, or freeing resources.
  4. Use custom error messages to make debugging easier.

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