🔥 10 JavaScript Tips with Code Snippets You Should Know

Hey devs! 👋

Whether you're just starting with JavaScript or already knee-deep in frameworks, it's always a good idea to keep your core JS skills sharp.

Here are 10 simple but powerful JavaScript tips, each with an example you can copy-paste and play with right away.
Let’s dive in! 🧠💻

✅ 1. map() vs forEach() — Know When to Use

const numbers = [1, 2, 3, 4]; const mapped = numbers.map(num => num * 2); // returns new array const forEachResult = []; numbers.forEach(num => forEachResult.push(num * 2)); console.log(mapped); // [2, 4, 6, 8] console.log(forEachResult); // [2, 4, 6, 8] 

🧠 Tip: Use map() when you want to return a new array. Use forEach() when you just want to run side effects (like logging or pushing).

✅ 2. Optional Chaining Saves You from Errors

const user = { name: 'John', address: { city: 'Dhaka' } }; console.log(user?.address?.city); // 'Dhaka' console.log(user?.contact?.email); // undefined (no crash!) 

🧠 Tip: Use optional chaining (?.) to safely access deeply nested properties without throwing runtime errors.

✅ 3. Nullish Coalescing vs Logical OR

const count = 0; const result1 = count || 10; // 10 ❌ const result2 = count ?? 10; // 0 ✅ console.log(result1); // 10 console.log(result2); // 0 

🧠 Tip: Use ?? when you want to preserve valid falsy values like 0, false, or "".

✅ 4. Clean Object Access with Destructuring

const person = { name: "Alice", age: 28, location: "Chittagong" }; const { name, age } = person; console.log(name); // Alice console.log(age); // 28 

🧠 Tip: Destructuring makes your code more concise and readable, especially when dealing with props or API responses.

✅ 5. setTimeout Inside Loops — Use let, Not var

for (var i = 0; i < 3; i++) { setTimeout(() => console.log(i), 1000); // 3 3 3 ❌ } for (let i = 0; i < 3; i++) { setTimeout(() => console.log(i), 1000); // 0 1 2 ✅ } 

🧠 Tip: Use let in loops with async logic. var is function-scoped, let is block-scoped.

✅ 6. Convert String to Number Quickly

const str = "42"; console.log(+str); // 42 console.log(Number(str)); // 42 console.log(parseInt(str)); // 42 

🧠 Tip: The unary + operator is a fast and clean way to convert strings to numbers.

✅ 7. Copy Objects Without Side Effects

const original = { name: "Dev", age: 25 }; const copy = { ...original }; copy.name = "Code"; console.log(original.name); // Dev console.log(copy.name); // Code 

🧠 Tip: Use the spread operator { ...obj } to create shallow copies and avoid unintended mutations.

✅ 8. Filter Arrays Like a Pro

const numbers = [1, 2, 3, 4, 5, 6]; const even = numbers.filter(n => n % 2 === 0); console.log(even); // [2, 4, 6] 

🧠 Tip: .filter() returns a new array containing only the values that match your condition.

✅ 9. Check If an Object Is Empty

const obj = {}; const isEmpty = Object.keys(obj).length === 0; console.log(isEmpty); // true 

🧠 Tip: A simple and effective way to validate API responses, form data, and configs.

✅ 10. Default Parameters in Functions

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

🧠 Tip: Default parameters help you write cleaner functions without repetitive if checks.

These small, clean, and efficient JavaScript tips can have a big impact on your daily workflow.
They help write bug-free, readable, and maintainable code — whether you're building frontend UIs or backend services.

Got a favorite JS tip?
Let me know in the comments or share this with your fellow devs! 🚀