10 JavaScript Mistakes That Make You Look Like a Beginner

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Avoid These to Instantly Level Up Your Code

Everyone starts somewhere, but some JavaScript mistakes scream beginner. If your code is buggy, hard to read, or slow, chances are you’re making one (or more) of these common errors. The good news? They’re easy to fix.

Plus, if you ever need extra help, Javascript Developer Resources - Made by 0x3d.site has you covered with tools, articles, and trending discussions.

1. Ignoring const and let

Stop using var—it’s outdated and causes weird scope issues. Instead:

const name = 'Alice'; // Use const if the value won't change
let age = 25; // Use let if the value might change

This makes your code more predictable and easier to debug. Need more best practices? Check out Developer Resources.

2. Forgetting to Handle Null and Undefined

Instead of writing fragile code like this:

console.log(user.profile.image);

Use optional chaining to avoid crashes:

console.log(user?.profile?.image);

Now, if user.profile is missing, your code won’t break.

3. Writing Bloated Functions

If your function is longer than 10–15 lines, it’s probably doing too much. Break it down:

function getFullName(user) {
  return `${user.firstName} ${user.lastName}`;
}

Shorter functions = easier debugging.

4. Relying Too Much on console.log()

Instead of spamming logs, use console.table() for better debugging:

console.table([{ name: 'Alice', age: 25 }, { name: 'Bob', age: 30 }]);

Find better debugging tricks on StackOverflow Trending.

5. Not Using Template Literals

Old way (ugh):

console.log('Hello, ' + name + '!');

New way (cleaner, easier to read):

console.log(`Hello, ${name}!`);

6. Copy-Pasting Code Instead of Using Functions

Bad practice:

console.log(`Hello, ${user.name}!`);
console.log(`Welcome, ${user.name}!`);

Better:

function greet(user) {
  return `Hello, ${user.name}!`;
}

This keeps your code DRY (Don’t Repeat Yourself).

7. Using == Instead of ===

== can cause unexpected type conversions. Always use ===:

console.log(5 == '5'); // true (bad)
console.log(5 === '5'); // false (good)

This avoids unexpected bugs.

8. Writing Code Without Comments

Future you (or another developer) will hate you if your code is unreadable. Leave clear, short comments:

// Calculate total price with tax
const total = price * 1.1;

Find more clean coding tips in Articles.

9. Not Using Array Methods

Instead of this:

const newArr = [];
for (let i = 0; i < arr.length; i++) {
  newArr.push(arr[i] * 2);
}

Use .map(), which is cleaner and faster:

const newArr = arr.map(num => num * 2);

10. Not Staying Updated

JavaScript moves fast. Instead of wasting time searching everywhere, just check Trending Repositories.

Fix These Mistakes & Write Better Code

Avoiding these mistakes will instantly make your JavaScript cleaner, faster, and easier to maintain.

Need more help? Bookmark javascript.0x3d.site—your one-stop resource for everything JavaScript.

Happy coding! 🚀

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