9 Clean Code Principles To Keep In Mind

Writing clean code isn't just about aesthetics—it's about writing code that is easy to read, maintain, and extend. Here are 9 fundamental principles to help you write cleaner, more professional code.

1. Meaningful Names

Choose names that clearly reveal the purpose of variables, functions, and classes.

Bad:

let d;
d = new Date();

Good:

let currentDate = new Date();

2. One Function, One Responsibility

Each function should do one thing and do it well.

Bad:

function getUserDataAndRender() {
  fetchUser();
  renderUser();
}

Good:

function fetchUser() {
  // fetch logic
}

function renderUser() {
  // render logic
}

3. Avoid Magic Numbers

Use named constants to make your code more understandable.

Bad:

if (user.age > 18) {
  // logic
}

Good:

const LEGAL_AGE = 18;
if (user.age > LEGAL_AGE) {
  // logic
}

4. Use Descriptive Booleans

Boolean names should express a condition.

Bad:

let flag = true;

Good:

let isUserLoggedIn = true;

5. Keep Code DRY (Don't Repeat Yourself)

Repeated logic increases the chance of bugs. Reuse your code.

Bad:

calculateTotal(price, tax);
calculateTotal(price, tax);

Good:

function calculateTotal(price, tax) {
  return price + price * tax;
}

let total = calculateTotal(price, tax);

6. Avoid Deep Nesting

Too many nested blocks can make code hard to read. Return early or use guard clauses.

Bad:

if (user) {
  if (user.isActive) {
    // logic
  }
}

Good:

if (!user || !user.isActive) return;
// logic

7. Comment Why, Not What

Explain the intent behind complex code.

Bad:

// loop through array
for (let i = 0; i < items.length; i++) {
  // ...
}

Good:

// Reorder items by priority before processing
for (let i = 0; i < items.length; i++) {
  // ...
}

8. Limit Function Arguments

Avoid too many parameters. Group related data.

Bad:

function createUser(name, age, email, address) {
  // logic
}

Good:

function createUser({ name, age, email, address }) {
  // logic
}

9. Code Should Be Self-Explanatory

Aim to write code that doesn’t need comments to be understood.

Bad:

let a = 5;
let b = 10;
let c = a + b;

Good:

let numberOfApples = 5;
let numberOfOranges = 10;
let totalFruits = numberOfApples + numberOfOranges;

Final Thoughts

Clean code is not a luxury; it's a necessity. Following these principles will make your code easier to debug, extend, and collaborate on. Remember, code is read more often than it is written—make it readable.