Writing Code for Humans, Not Just Machines

In the world of software development, writing code that works is just the beginning. As developers, we often focus on making our code functional, but we sometimes forget that code is meant to be read and understood by humans as well as machines. JavaScript, like all programming languages, can be written in many different ways, but writing human-readable JavaScript is a crucial skill for building maintainable, scalable applications.

Human-readable code is code that is easy for other developers (or even your future self) to understand. It reduces cognitive load, allows teams to collaborate more effectively, and simplifies debugging and updating code over time. In this article, we'll explore why writing human-readable JavaScript is essential, and we'll discuss best practices for achieving this.

Why Human-Readable JavaScript Matters

1. Collaboration: In a team environment, it's common for multiple developers to work on the same codebase. Writing human-readable code ensures that your team members can easily understand your logic, which leads to smoother collaboration and faster development cycles.

2. Maintenance: Code is read more often than it's written. You or another developer may need to come back to a piece of code months or even years after it was originally written. Clear and readable code makes maintenance tasks, such as fixing bugs or adding new features, much easier.

3. Debugging: When issues arise, well-written code is easier to debug. Human-readable code makes it faster to spot mistakes, understand the flow of logic, and implement the necessary fixes.

4. Onboarding: When new developers join a project, they need to quickly get up to speed with the codebase. Writing clean and readable code helps new team members understand the structure and purpose of the code, reducing onboarding time.

Best Practices for Writing Human-Readable JavaScript

1. Use Descriptive Variable and Function Names

Your variables and functions should clearly describe their purpose. Avoid single-letter variable names like x or y unless you're working in very small scopes where the meaning is obvious. Instead, use meaningful names that describe the data they hold or the action they perform.

Bad Example:

function a(x, y) {
  return x * y;
}

Good Example:

function calculateArea(width, height) {
  return width * height;
}

In the good example, it's immediately clear what the function does and what the arguments represent. This clarity makes the code easier to understand at a glance.

2. Keep Functions Small and Focused

Functions should do one thing and do it well. Large, multi-purpose functions are difficult to understand and maintain. Breaking code down into smaller, focused functions increases readability and makes it easier to test and debug.

Bad Example:

function processUserData(user) {
  // Validate user
  if (!user.name || !user.email) {
    return 'Invalid user data';
  }

  // Save user
  database.save(user);

  // Send email
  emailService.sendWelcomeEmail(user.email);

  return 'User processed successfully';
}

Good Example:

function validateUser(user) {
  return user.name && user.email;
}

function saveUser(user) {
  database.save(user);
}

function sendWelcomeEmail(user) {
  emailService.sendWelcomeEmail(user.email);
}

function processUserData(user) {
  if (!validateUser(user)) {
    return 'Invalid user data';
  }

  saveUser(user);
  sendWelcomeEmail(user);

  return 'User processed successfully';
}

In the good example, each function has a single responsibility. The main processUserData function becomes easier to read because the logic is separated into smaller, descriptive pieces.

3. Write Comments Where Necessary

Comments are a great way to explain why something is done a certain way or to clarify non-obvious code. However, comments should not be used as a crutch for writing unclear code. Use comments to supplement, not to compensate for, poorly written code.

Bad Example:

// This multiplies width and height to get the area
function calculateArea(width, height) {
  return width * height;
}

Good Example:

// Calculates the area of a rectangle
function calculateArea(width, height) {
  return width * height;
}

In the bad example, the comment is redundant because the code itself is clear. In the good example, the comment adds useful context by explaining that the function calculates the area of a rectangle specifically.

4. Use Consistent Formatting and Indentation

Consistent formatting makes code more readable and easier to follow. Whether you're using tabs or spaces, single quotes or double quotes, it's important to be consistent. Tools like Prettier or ESLint can help enforce consistent formatting across your codebase.

Bad Example:

function calculateArea(width,height){
  return width * height;}

Good Example:

function calculateArea(width, height) {
  return width * height;
}

In the good example, consistent indentation and spacing make the code easier to read.

5. Avoid Deep Nesting

Deeply nested code can be difficult to follow and maintain. Try to flatten your code by using early returns or separating logic into smaller functions.

Bad Example:

function processUser(user) {
  if (user) {
    if (user.isActive) {
      if (user.hasProfile) {
        return 'User is valid';
      }
    }
  }
  return 'Invalid user';
}

Good Example:

function processUser(user) {
  if (!user || !user.isActive || !user.hasProfile) {
    return 'Invalid user';
  }

  return 'User is valid';
}

In the good example, the nesting is reduced by using an early return. This makes the code easier to read and understand.

6. Avoid Magic Numbers

Magic numbers are numbers that appear in code without explanation. They can make code harder to understand and maintain. Instead, use named constants to make your code more descriptive.

Bad Example:

if (score > 60) {
  return 'Pass';
}

Good Example:

const PASSING_SCORE = 60;

if (score > PASSING_SCORE) {
  return 'Pass';
}

In the good example, the magic number 60 is replaced by a constant, which makes the code more readable and easier to maintain.

7. Handle Errors Gracefully

Error handling should be clear and consistent. Always provide meaningful error messages and avoid using generic or unclear errors.

Bad Example:

function divide(a, b) {
  if (b === 0) {
    throw 'Error';
  }
  return a / b;
}

Good Example:

function divide(a, b) {
  if (b === 0) {
    throw new Error('Division by zero is not allowed');
  }
  return a / b;
}

In the good example, the error message provides clear information about what went wrong, making it easier to debug.

Conclusion

Writing human-readable JavaScript is an essential skill that goes beyond simply making your code work. It's about writing code that other developers (and your future self) can easily understand, maintain, and debug. By following best practices like using descriptive names, keeping functions small, writing meaningful comments, and using consistent formatting, you can write code that not only works but is also a pleasure to read.

Remember, code is for humans as much as it is for machines. By prioritizing readability, you'll create code that is more maintainable, scalable, and efficient in the long run.