How to Fix "SyntaxError: Unexpected Token" in JavaScript

By David Kim Jul 11, 2026 6 min read Programming

"SyntaxError: Unexpected token" means the JavaScript parser encountered an unexpected character. It usually indicates a syntax mistake or invalid JSON.

Invalid JSON Parsing

The most common cause is JSON.parse() receiving malformed JSON. Common JSON mistakes: trailing commas (not allowed in JSON), single quotes instead of double quotes, missing quotes around keys, or undefined values. Always validate JSON with tools like JSONLint before parsing. Use try/catch around JSON.parse().

Missing or Extra Brackets

Unmatched parentheses, brackets, or braces cause unexpected token errors. Check that every opening character has a matching closing character. Use an editor with bracket matching and syntax highlighting. Indent your code to visually verify bracket alignment.

Import/Export Errors

Mixing CommonJS (require) and ES modules (import) can cause unexpected token errors. Ensure your package.json has "type": "module" for ES modules. Use .mjs extension for ES modules and .cjs for CommonJS. Check the import path and default vs named exports.

String and Template Literal Problems

Unclosed strings or template literals cause the parser to misinterpret the rest of the code. Ensure all strings are closed with the correct quote type. Backtick template literals must be closed with backticks. Nested quotes need careful handling.

Async/Await Context Errors

Using await outside an async function causes "Unexpected token". Ensure await is only used inside functions declared with async. Top-level await is supported in ES modules but not in CommonJS scripts.