Practical Debugging Tips for JavaScript Developers

Debugging is an inevitable part of a developer's life, because bugs are EVERYWHERE!

Effective debugging is more than just finding errors, it involves understanding how to prevent them in the first place and fix them when you can't avoid them.
In this article let's talk about some practical debugging tips.

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1. Understand the Common Errors

To start, let's get familiar with the most common JavaScript errors. Here are a few to keep an eye on:

• Syntax Errors: Often due to typos or incorrect use of language rules.
• Runtime Errors: These occur as your program executes, like trying to call a function that doesn’t exist.
• Logical Errors: Perhaps the trickiest, these involve no exceptions but lead to incorrect results.

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2. Master the Console

The browser’s console is a powerful tool for debugging, so use it!

• Console Logging: Instead of using alert(), use console.log(), console.warn(), and console.error() to get insights into how your code is running without disrupting the flow with modal alerts.
• Assert Statements: Use console.assert() to test if a statement returns true and only print something to the console if the assertion fails.

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3. Leveraging Breakpoints

Breakpoints are your best friend in the debugging process:

• Set Breakpoints in DevTools: Use Chrome DevTools or Firefox Developer Tools to set breakpoints where execution will pause.
• Conditional Breakpoints: Set breakpoints that only trigger when a specific condition is met. This is useful for debugging loops or multi-conditional statements.

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4. Watch Expressions and Scope

While paused at a breakpoint:

• Watch Expressions: Add expressions to watch how values change over time. It helps you monitor the behavior of your code during the execution of specific blocks.
• Scope Panel: Check the Scope panel in your dev tools to understand the current context and see what variables are available.

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5. Using Network Tab to Debug API Calls

API calls can often be a source of bugs, so let's try to avoid them:

• Check the Network Tab: Ensure that the request is being made correctly and that the response is what you expect.
• Inspect Headers and Payloads: Verify that the headers and payloads of your API requests are correctly formatted.

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6. Handling Asynchronous Code

Debugging asynchronous code requires a slightly different approach:

• Promise Chains: Ensure promises are returning what you expect and catch any errors properly.
• Async/Await: Use try/catch blocks effectively to handle errors in async functions.

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7. Tools and Plugins to Enhance Debugging

Explore tools and plugins that can further help with debugging:

• Linting Tools: Use ESLint to catch many common bugs before they happen.
• Debugging Extensions: Extensions like Augury (for Angular) or React Developer Tools can provide deeper insights into specific frameworks.

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Bugs? 🐞

Effective debugging in JavaScript is as much about preventing errors as it is about fixing them. By learning these practical tips you can significantly reduce debugging time and increase your efficiency as a developer.
Share any tools or techniques that have changed the way you debug your code.
Let’s learn from each other and improve our craft together!

Thanks for reading,

Pachi 💚

P.S. Wanna join a community of JavaScript Developers? Click here!