The junior developer‘s guide to writing super clean and readable code

As a junior developer, one of the most powerful ways you can level up your skills and stand out to your teammates and managers is by writing exceptionally clean, readable code.

I know, I know – when you‘re just starting out, it‘s tempting to focus solely on getting your code to work, by any means necessary. But trust me, taking the time to learn and apply best practices for clean code will pay massive dividends throughout your career.

Why clean code matters

Let‘s start with a gut check: How much time do you spend actually writing new code, versus reading and trying to understand existing code? If you‘re like most developers, you probably spend a lot more time reading code than writing it.

In fact, a study by Carnegie Mellon University found that developers spend about 58% of their time on "comprehension activities", like reading and navigating code. Only 12% of their time was spent writing new code!

Now imagine how much more productive you and your team could be if all that existing code was easy to read and understand. That‘s the power of clean code.

But the impact goes beyond just saving time. Research has shown that messy, hard-to-understand code is strongly correlated with higher bug rates, slower development velocity, and even lower job satisfaction among developers.

On the flip side, teams that prioritize clean code tend to see:

• 40-90% fewer bugs
• 2-5x faster development speed
• Higher job satisfaction and lower turnover

So as a junior developer, making clean code a priority is one of the best investments you can make in your career. It will make you more productive, more valuable to your team, and more satisfied in your work.

Principles of clean code

So what exactly makes code "clean"? While there‘s no single definition, there are several core principles that most experienced developers agree on. Let‘s dive into each one.

1. Write code for humans, not just computers

It‘s important to remember that code is read much more often than it is written. So while your code needs to be correct and efficient, it also needs to be easily understood by other developers (including your future self).

Before you write any code, take a moment to think about how it will be read and understood by others. Some things to consider:

• What would someone need to know to understand this code?
• What questions might they have?
• How can I structure it and name things to make it as intuitive as possible?

One helpful trick is to imagine you‘re writing for a junior developer with no context on the project. Pretend they will be maintaining your code after you‘ve moved on to another team. How can you make it as easy as possible for them to understand what your code does and how it works?

2. Follow standard conventions

One of the easiest ways to make your code more readable is to follow the standard conventions for your language and framework. This includes things like:

• Naming conventions for variables, functions, classes, etc.
• Indentation and formatting (e.g. using spaces vs tabs, line length limits)
• Project structure and organization
• Comment and documentation styles

Most languages have widely accepted style guides that specify these conventions. For example:

• Python: PEP 8
• JavaScript: Airbnb Style Guide or Standard JS
• Ruby: RuboCop
• Swift: SwiftLint

Following these conventions makes your code more consistent and predictable, which makes it easier for other developers to read and work with.

Many development teams also establish their own conventions through a shared style guide. If your team has one, make sure you study it and follow it closely.

3. Keep functions small and focused

Functions are the building blocks of readable code. A well-written function should do one thing, and do it well.

Some characteristics of a clean function:

• Has a clear, descriptive name that conveys its purpose
• Does only one thing
• Is small, typically less than 20 lines of code
• Has minimal side effects and dependencies
• Uses clear and consistent naming for arguments and variables

If you find yourself writing a function that does multiple things, or is more than 20-30 lines long, consider breaking it up into smaller, more focused functions. For example:

// Instead of this:
function processUserInput(input) {
  // Validate input
  if (!isValid(input)) {
    showError(‘Invalid input‘);
    return;
  }

  // Process input
  const result = /* complex processing logic */;

  // Format and display result
  const formattedResult = formatResult(result);
  displayResult(formattedResult);
}

// Do this:
function processUserInput(input) {
  if (!isValid(input)) {
    handleInvalidInput(input);
    return;
  }

  const result = processInput(input);
  handleResult(result);
}

function handleInvalidInput(input) {
  showError(‘Invalid input‘);
  // maybe log the error or do some other handling
}

function processInput(input) {
  // complex processing logic
  return result;
}

function handleResult(result) {
  const formattedResult = formatResult(result);
  displayResult(formattedResult);
}

By breaking the original function into smaller, single-purpose functions, we‘ve made the code much easier to understand and maintain. Each function does one clear thing, which makes the overall flow of the program easier to follow.

4. Make your code self-explanatory

Whenever possible, your code should explain itself. A reader should be able to understand what your code does without relying heavily on comments or external documentation.

Some ways to make your code more self-explanatory:

• Use clear, descriptive names for variables, functions, and classes
• Keep functions and classes small and focused
• Use language features like enums and constants to encode meaning
• Encapsulate complex logic or formulas behind descriptive function names
• Avoid magic numbers or string literals scattered throughout the code
• Use meaningful and consistent naming patterns, like verb phrases for functions

For example, compare these two code snippets:

// Unclear and unexplained
function calc(x) {
  return x * 42;
}

// Clear and self-explanatory
const MEANING_OF_LIFE = 42;

function calculateProductLifetimeValue(purchasePrice) {
  return purchasePrice * MEANING_OF_LIFE;
}

The first snippet leaves the reader with questions: What does this function do? What does 42 mean here? Why is it multiplying by 42?

The second snippet answers those questions directly in the code itself. The function and variable names, along with the use of a constant, make it immediately clear what the code is doing and why.

Strive to write code that speaks for itself like this. It will save countless hours of confusion and head-scratching for your fellow developers (and your future self).

5. Refactor regularly

No matter how clean your code starts out, it will get messy over time as requirements change and new features are added. That‘s why it‘s important to regularly refactor your code to keep it clean and maintainable.

Refactoring is the process of restructuring existing code without changing its external behavior. It‘s like tidying up your codebase, organizing and optimizing it to be as clean and efficient as possible.

Some common refactoring techniques:

• Renaming variables, functions, and classes to be more descriptive
• Breaking up large functions into smaller, single-purpose functions
• Removing duplicated code
• Simplifying complex conditional logic
• Replacing magic numbers and string literals with constants
• Improving performance by optimizing loops or data structures

Whenever you‘re working with a piece of code, look for opportunities to refactor and clean it up. Some good times to refactor:

• When you‘re fixing a bug, see if you can also clean up the surrounding code
• After adding a new feature, review the code you‘ve changed and look for refactoring opportunities
• During code reviews, suggest refactorings to improve the overall quality of the codebase
• Periodically, set aside dedicated time (like a half-day every month) for refactoring

The key to successful refactoring is to take small, incremental steps and test thoroughly after each change. Avoid the temptation to rewrite large swaths of code all at once, as this is more likely to introduce bugs.

Use tools like unit tests and version control to make sure your refactorings don‘t change the external behavior of the code. If your project doesn‘t already have good test coverage, writing tests before you refactor can give you the confidence to clean up the code without fear of breaking things.

The impact of clean code

Writing clean code isn‘t just about making things look pretty or following arbitrary rules. It has a direct, measurable impact on the success of your software projects.

Research by Stripe found that developers spend 31% of their time dealing with technical debt – the cost of additional rework caused by choosing an easy solution now instead of a better approach that would take longer. A lot of this technical debt comes from messy, hard-to-maintain code.

On the other hand, a study by the University of Zurich found that projects with cleaner code had 40-90% fewer bugs than projects with lower code quality. They also found that cleaner code was strongly correlated with faster development speed, by a factor of 2x to 5x.

Cleaner code also has big benefits for team dynamics and developer happiness. A survey by Stack Overflow found that developers who were satisfied with their company‘s code quality were 3.2x more likely to be satisfied with their job overall.

So by writing clean code, you‘re not only making things easier for yourself and your teammates in the short term. You‘re also setting your project up for long-term success and making your workplace a happier, more satisfying place to be.

Putting it into practice

As a junior developer, the best way to get better at writing clean code is to practice, get feedback, and learn from more experienced developers.

Some specific things you can do:

• Find a mentor or code reviewer who can give you detailed feedback on your code‘s readability and maintainability
• Read open source code from well-respected projects and developers. Notice how they structure their code and what makes it easy or hard to read
• Practice refactoring messy code, either in your own projects or by contributing to open source
• Learn and use tools that help you maintain code quality, like linters, formatters, and static analyzers
• Pair program with more senior developers and observe how they approach writing clean code
• Read books on the topic, like "Clean Code" by Robert C. Martin or "Code Complete" by Steve McConnell

Remember, learning to write clean code is a journey, not a destination. Even the most experienced developers are always looking for ways to improve the clarity and maintainability of their code.

As a junior developer, you have a huge opportunity to form good habits early and set yourself up for a successful, impactful career in software development. By making clean code a priority from day one, you‘ll be well on your way to becoming the kind of developer that teams fight over.

So go forth and write some beautifully clean code! Your teammates (and your future self) will thank you.