Debugging Techniques Explained

Key Concepts

Debugging is the process of finding and resolving issues in your code. The key techniques include:

• Using Console Logs
• Breakpoints
• Error Stack Traces
• Debugger Statement
• Code Reviews
• Automated Testing

Using Console Logs

Console logs are a simple yet effective way to debug your code. By printing messages to the console, you can track the flow of your program and inspect variable values.

console.log("Start of function");
let x = 10;
console.log("Value of x:", x);
x += 5;
console.log("Value of x after addition:", x);
    

Breakpoints

Breakpoints allow you to pause the execution of your code at specific points. This enables you to inspect the state of your program and step through the code line by line.

function add(a, b) {
    let result = a + b;
    return result;
}

let sum = add(5, 10);
console.log(sum);
    

Error Stack Traces

Error stack traces provide a detailed report of where an error occurred and the sequence of function calls that led to it. This helps you pinpoint the source of the error.

function divide(a, b) {
    if (b === 0) {
        throw new Error("Division by zero");
    }
    return a / b;
}

try {
    let result = divide(10, 0);
    console.log(result);
} catch (error) {
    console.error(error.stack);
}
    

Debugger Statement

The debugger statement pauses the execution of your code and opens the debugging tools in your browser. This is useful for inspecting variables and stepping through code.

function multiply(a, b) {
    debugger;
    let result = a * b;
    return result;
}

let product = multiply(5, 6);
console.log(product);
    

Code Reviews

Code reviews involve having other developers inspect your code for potential issues. This collaborative approach helps catch bugs and improve code quality.

function subtract(a, b) {
    return a - b;
}

let difference = subtract(20, 10);
console.log(difference);
    

Automated Testing

Automated tests are scripts that verify your code behaves as expected. They help catch bugs early and ensure that changes do not introduce new issues.

function isEven(num) {
    return num % 2 === 0;
}

console.assert(isEven(4), "4 should be even");
console.assert(!isEven(5), "5 should not be even");
    

Examples and Analogies

Imagine debugging as solving a mystery:

• Using Console Logs: Like leaving clues for yourself to follow the story.
• Breakpoints: Like pausing a movie to inspect each scene.
• Error Stack Traces: Like a detective's report detailing the crime scene and suspects.
• Debugger Statement: Like summoning a detective to the scene for a closer look.
• Code Reviews: Like consulting with other detectives to gather more insights.
• Automated Testing: Like setting up security cameras to catch any suspicious activity.