JavaScript best practices for beginners

Gambolthemes March 2, 2025

If you’re new to JavaScript, following best practices will help you write clean, efficient, and maintainable code. Here are some key guidelines:

1. Use `let` and `const` Instead of `var`

let allows you to declare variables with block scope.
const is for variables that shouldn’t be reassigned.

let age = 25; // Can be reassigned
const name = "John"; // Cannot be reassigned

2. Use Strict Mode

Strict mode helps catch common mistakes and enforces safer coding practices.

"use strict";

3. Use Meaningful Variable and Function Names

Choose names that describe what the variable or function does.

let userAge = 25;
function calculateTotal(price, tax) {
  return price + tax;
}

4. Keep Functions Small and Focused

Each function should do only one thing.

function getUserName(user) {
  return user.name;
}

function getUserAge(user) {
  return user.age;
}

5. Avoid Global Variables

Global variables can cause conflicts. Instead, encapsulate variables inside functions or modules.

function example() {
  let localVar = "I'm local";
}

6. Use Template Literals Instead of String Concatenation

Makes string manipulation easier.

let name = "Alice";
console.log(`Hello, ${name}!`);

7. Handle Errors with `try...catch`

Always handle possible errors to prevent crashes.

try {
  let result = someFunction();
} catch (error) {
  console.error("An error occurred:", error);
}

8. Use Array Methods Instead of Loops

Methods like .map(), .filter(), and .reduce() make code cleaner.

let numbers = [1, 2, 3, 4];
let squared = numbers.map(num => num * num);
console.log(squared); // [1, 4, 9, 16]

9. Use Default Parameters in Functions

Prevents errors when arguments are missing.

function greet(name = "Guest") {
  console.log(`Hello, ${name}!`);
}
greet(); // Hello, Guest!

10. Avoid `==`, Use `===` Instead

=== checks both value and type, reducing unexpected bugs.

console.log(5 === "5"); // false
console.log(5 == "5"); // true (but risky!)

11. Use Destructuring for Cleaner Code

Extract values from objects or arrays easily.

const user = { name: "Bob", age: 30 };
const { name, age } = user;
console.log(name); // Bob

12. Use Arrow Functions Where Appropriate

Shorter syntax and better readability.

const multiply = (a, b) => a * b;
console.log(multiply(2, 3)); // 6

13. Use `async/await` for Handling Promises

Easier to read than .then() chains.

async function fetchData() {
  try {
    let response = await fetch("https://api.example.com/data");
    let data = await response.json();
    console.log(data);
  } catch (error) {
    console.error("Error fetching data:", error);
  }
}

14. Keep Your Code DRY (Don’t Repeat Yourself)

Avoid repeating code; use functions or reusable components.

function calculateDiscount(price, discount) {
  return price - price * discount;
}

15. Use Console Logging Wisely

Use console.log() for debugging but remove it from production code.

console.log("Debugging message");

For better debugging:

console.table(myArray);
console.error("This is an error message");
console.warn("This is a warning");

16. Comment Wisely

Write comments only where necessary to explain complex logic.

// Converts Celsius to Fahrenheit
function toFahrenheit(celsius) {
  return (celsius * 9) / 5 + 32;
}

17. Keep Your Code Formatted

Use tools like Prettier or ESLint to format and lint your code automatically.

By following these best practices, your JavaScript code will be more readable, maintainable, and efficient. 🚀

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