SyntaxError

SyntaxError is thrown when the JavaScript engine encounters code that doesn't conform to the language syntax. This is caught at parse time, before the code executes.

Common causes

• Missing or extra brackets, parentheses, or braces
• Invalid or unexpected tokens
• Malformed JSON when using JSON.parse()
• Using reserved keywords as variable names
• Missing commas in object literals or arrays

How to fix it

• Use an editor with syntax highlighting and bracket matching
• Run a linter like ESLint to catch syntax errors early
• Validate JSON strings before parsing with JSON.parse()
• Check for matching pairs of brackets, braces, and quotes
• Use Prettier or similar formatters to auto-fix formatting

Example

// Error examples
const obj = { name: "Alice" age: 30 };
// SyntaxError: Unexpected identifier 'age'

JSON.parse("{ invalid json }");
// SyntaxError: Unexpected token i in JSON

// Fix: add missing comma
const obj = { name: "Alice", age: 30 };

// Fix: use valid JSON
JSON.parse('{ "name": "Alice" }');

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