10 JavaScript Tips Every Beginner Should Know

These are the things I wish someone had told me earlier. None are advanced — they just quietly make your code better.

1. Default to const

Use const unless you know the value will change; then use let. Never var.

2. Template literals beat concatenation

const msg = `Hi ${name}, you have ${count} messages`;

3. Use guard clauses to avoid nesting

function save(user) {
  if (!user) return;
  // happy path stays flat
}

4. Use === not ==

== does surprising type coercion. === compares value and type.

5. Array methods over loops

const names = users.filter(u => u.active).map(u => u.name);

6. Optional chaining saves you from crashes

user?.profile?.avatar returns undefined instead of throwing.

7. Nullish coalescing for defaults

const page = input ?? 1; uses 1 only when input is null or undefined.

8. Destructure what you need

const { title, date } = post;

9. console.log is a debugging superpower

Log early, log often. console.table() for arrays of objects is a hidden gem.

10. Read the error message

The stack trace usually tells you the file and line. Slow down and read it — it's answering the question you're about to Google.