Fix JavaScript SyntaxError: Unexpected Token and More (2025 Guide)

Fix JavaScript SyntaxError: Unexpected Token and More in JavaScript - 2025 Guide

Posted on: March 12, 2025

If you’ve seen a "SyntaxError" like "Unexpected token" in JavaScript, it means there’s a mistake in your code’s grammar. Don’t worry—it’s a common issue, and in this guide, I’ll break down why it happens and how to fix it quickly.

What Causes a "SyntaxError"?

A "SyntaxError" occurs when JavaScript can’t parse your code due to incorrect syntax. Here are the top culprits:

• Missing or Extra Symbols: Forgotten parentheses, brackets, or semicolons.
• Unexpected Tokens: A character or keyword is out of place.
• Invalid JSON: Parsing malformed JSON strings.

Here’s an interactive example (open your browser console with F12 to see the error):

In this example, an extra closing parenthesis ) causes a "SyntaxError: Unexpected token ')'".

How to Fix It: 3 Solutions

Let’s tackle this error with practical steps:

(Diagram: Developer writes code, gets error, checks syntax/JSON, fixes issue.)

Solution 1: Check Parentheses and Brackets

Ensure all opening and closing symbols match:

// Wrong
function sayHello( {
  console.log("Hello!";
}

// Fixed
function sayHello() {
  console.log("Hello!");
}

Missing or extra (), {}, or [] is a frequent cause—count them carefully!

Solution 2: Fix Unexpected Tokens

Look for misplaced characters or keywords:

// Wrong
let x = 5 + ; // SyntaxError: Unexpected token ';'

// Fixed
let x = 5;

The error message often points to the exact line—start there!

Solution 3: Validate JSON

When parsing JSON, ensure it’s correctly formatted:

// Wrong
const json = '{"name": "John",}';
JSON.parse(json); // SyntaxError: Unexpected token }

// Fixed
const json = '{"name": "John"}';
const data = JSON.parse(json); // Works fine

Use a JSON validator (like jsonlint.com) to spot errors in complex strings.

Quick Checklist

• Are all parentheses and brackets balanced?
• Is there an unexpected character or keyword?
• If using JSON, is it valid? (Test with JSON.parse.)

Conclusion

A "SyntaxError" like "Unexpected token" can stop your code in its tracks, but it’s usually a quick fix once you spot the mistake. With these tips, you’ll be debugging like a pro. Got another JavaScript error bugging you? Let me know in the comments!

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