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Debugging Tips and Tricks: How to find bugs like Sherlock Holmes

by Avalon Studios

Debugging is like being a detective – you need to piece together clues to solve the mystery of why your code isn’t working. Bugs can be tricky to identify and fix, but with the right tools and techniques, you can solve them like Sherlock Holmes. In this article, we’ll explore some tips and tricks for identifying and fixing common bugs and errors in web development, with a mix of JavaScript, PHP and CSS code examples.

Use console.log() to print variables and objects

When you’re not sure what’s going on with your code, console.log() can be your best friend. This function logs the value of a variable or object to the console, so you can see what’s happening at any given point in your code. For example:

    let x = 5;
console.log(x); // Logs "5" to the console

You can also log multiple variables or objects at once:

    let x = 5;
let y = "Hello";
console.log(x, y); // Logs "5" and "Hello" to the console

This can help you identify where your code is going wrong, and what values your variables and objects are taking on at different points in your program.

Check for syntax errors with a linter

Syntax errors can be frustratingly hard to spot, especially in larger codebases. A linter can help by checking your code for common syntax errors and highlighting them for you. For example, in JavaScript, you can use ESLint:

    // Install ESLint with npm or yarn
// Then create a .eslintrc.json file with your configuration
  "extends": "eslint:recommended",
  "rules": {
    // Add custom rules here if needed

Then run ESLint on your code:

    npx eslint myfile.js

ESLint will highlight any syntax errors in your code, so you can fix them before they cause problems.

Use breakpoints to pause your code

Sometimes, you need to stop your code at a specific point to see what’s happening. This is where breakpoints come in. You can set a breakpoint in your code using the debugger keyword:

    let x = 5;
debugger; // Sets a breakpoint here
x += 10;
console.log(x); // Logs "15" to the console

When your code reaches the debugger keyword, it will pause execution, allowing you to inspect the current state of your program. You can then step through your code line by line, or resume execution until the next breakpoint.

Test your code in different browsers

Different browsers can interpret your code differently, which can lead to bugs and errors. To ensure your code works across different browsers, you should test it in as many browsers as possible. You can use a tool like BrowserStack to test your code in multiple browsers:

    const { Builder } = require('selenium-webdriver');
const fs = require('fs');

(async function example() {
  const driver = await new Builder().forBrowser('chrome').build();
  try {
    await driver.get('');
    await driver.findElement('q')).sendKeys('Selenium', Key.RETURN);
    await driver.wait(until.titleContains('Selenium'), 1000);
    const image = await driver.takeScreenshot();
    fs.writeFileSync('screenshot.png', image, 'base64');
  } finally {
    await driver.quit();

Here we ise async/await keywords to declare variables and handle promises respectively. It also uses destructuring to import the Builder class from the selenium-webdriver package and the fs module from Node.js. Additionally, it uses arrow functions and template literals to make the code more concise and readable.

Break your code into smaller pieces

Large, complex code can be difficult to debug. To make your code more manageable, you should break it into smaller, more modular pieces. This can make it easier to test and debug individual components, and can make your code more reusable. For example, in PHP, you can break your code into functions:

    function greet($name) {
  echo "Hello, $name!";

greet("Alice"); // Outputs "Hello, Alice!"
greet("Bob"); // Outputs "Hello, Bob!"

This code defines a function called greet() that takes a name as an argument and outputs a greeting. You can call this function with different names to output different greetings.

In CSS, you can break your code into classes:

    .red {
  color: red;

.blue {
  color: blue;

This code defines two classes, .red and .blue, that set the color of text to red and blue, respectively. You can then apply these classes to different elements in your HTML to change their colors.

Debugging can be a frustrating part of the web development process, but with the right tools and techniques, you can solve even the trickiest of bugs. By using console.log() to print variables and objects, checking for syntax errors with a linter, using breakpoints to pause your code, testing your code in different browsers, and breaking your code into smaller pieces, you can become a debugging master like Sherlock Holmes.

Happy coding!

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