30 Days of JavaScript: Error Handling and Debugging — Day 10

30 Days of Javascript Series by DopeThemes

Programming is an intricate ballet of solving problems and implementing ideas. However, along the journey, you may stumble upon some unforeseen errors or quirky behaviors in your code. On Day 10 of our exploration into JavaScript, we delve into the very essence of debugging and error handling to guide your code towards perfection.

Deciphering Errors

Errors are not merely stumbling blocks but guides that steer you towards the right path. Understanding errors in JavaScript requires a keen eye for detail. JavaScript throws a variety of errors, such as SyntaxError, ReferenceError, and TypeError. These errors provide clues on where and why the code has faltered.

For example:

console.log(Hello, World!);

This code results in a SyntaxError, as the string is not enclosed in quotes. The error message acts as a beacon, illuminating the area in need of correction.

The Console

The console is an indispensable tool in a developer’s arsenal. It serves as a window into the runtime environment. console.log() can be used to observe values, test snippets of code, and track the execution flow.

let sum = 0;

for (let i = 0; i <= 10; i++) {
    sum += i;
    console.log(<code>Sum so far: ${sum}</code>);

This code prints the running total at each iteration, offering insights into the loop’s mechanics.


Breakpoints allow you to halt the execution at specific lines, observing the state of variables and the control flow. Modern browsers offer developer tools with breakpoints that empower developers to peruse through code execution line by line.

Error Handling with Try-Catch

To achieve an impeccable user experience, handling errors gracefully is paramount. The trycatch statement in JavaScript encapsulates this principle. Code that can potentially throw an error is placed within the try block. If an error occurs, the code inside the catch block is executed.

try {
    let name = 'John Doe';
    console.log(nam); // ReferenceError since the variable is named "name" not "nam"
} catch (error) {
    console.log('An error occurred:', error);

This ensures that the application does not break, and the error can be handled smoothly.

Error Handling with Custom Exceptions

Sometimes, an even higher degree of control is required. Custom exceptions can be thrown using the throw statement, allowing for specific error handling.

try {
    let age = 17;
    if (age &lt; 18) {
        throw new Error('Age restriction not met.');

    console.log('Access granted.');
} catch (error) {
    console.log(<code>Error: ${error.message}</code>);

Advanced Debugging Techniques

As the sophistication of applications grows, so does the need for advanced debugging tools. Linters such as ESLint can assist in identifying issues at the code level. Integration with advanced features of browser developer tools, such as Chrome Developer Tools, can also be an invaluable asset for complex applications.


Debugging and error handling are akin to fine arts. The finesse with which a developer handles errors defines the robustness of an application. Through a meticulous understanding of errors, adept use of the console, breakpoints, and the judicious application of try-catch blocks, you can craft a masterpiece that stands the test of time.

Day 10 is a wrap. As we continue our sojourn into the depths of JavaScript, let’s carry forward the wisdom garnered today, evolving into architects of impeccable code.

Next: 30 Days of JavaScript: Performance Optimization Techniques — Day 11

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