Skip to main content

How to Resolve "SyntaxError: Illegal return statement" in JavaScript

The SyntaxError: Illegal return statement is a fundamental error in JavaScript that occurs when a return statement is used outside of a function. This error is a direct violation of the language's syntax rules, as the return keyword has a very specific purpose that is tied exclusively to functions.

This guide will explain the core purpose of the return statement, show you the common mistakes that lead to this error, and provide the correct solutions, such as using break to exit loops.

The Core Problem: The Purpose of a return Statement​

The return statement has two jobs:

  1. To immediately stop the execution of a function.
  2. To (optionally) pass a value back to the code that called the function.

Consider this valid example:

function calculateTotal(price, tax) {
  let total = price + tax;
  return total; // Stop the function and send `total` back.
}

// The value returned from the function is assigned to the `result` variable.
let result = calculateTotal(10, 2);
console.log(result); // Output: 12
note

The error "Illegal return statement" occurs because if there is no function, there is no "caller" to return a value to, and no function execution to stop.

Cause 1 (Most Common): return at the Top Level of a Script​

This is the most direct violation of the rule. Placing return in the global scope of a file has no logical meaning in JavaScript.

Example of problem:

// Problem: This `return` statement is not inside a function.
let myValue = 'hello';
return myValue;

Error Output:

Uncaught SyntaxError: Illegal return statement

Solution: code at the top level of a script does not need to "return" values. If your goal is to make a value available to other scripts, you should export it from your module.

// Correct: Export the value to make it available to other modules.
export let myValue = 'hello';

If you are in a simple, single-file context and just wanted to end the script, you can simply let the script end naturally. There is no return equivalent for a whole script file.

Cause 2: return Inside a Loop or if Block (Not within a Function)​

A common mistake for beginners is to use return as a way to "exit" a loop or a conditional block. However, these blocks do not create a valid context for a return statement unless they are themselves inside a function.

Example of problem:

let numbers = [1, 2, 3, 4, 5];

for (let num of numbers) {
  if (num > 3) {
    // Problem: This `return` is not inside a function.
    return;
  }
  console.log(num);
}

Solution A: Wrap the Logic in a Function​

If you need to return a value or stop execution, your logic must be enclosed in a function.

function processNumbers(numbers) {
  for (let num of numbers) {
    if (num > 3) {
      // Correct: This is now valid because it exits the `processNumbers` function.
      return; 
    }
    console.log(num);
  }
}

processNumbers([1, 2, 3, 4, 5]); // Output: 1, 2, 3

Output:

1
2
3

Solution B: Use the break Statement to Exit a Loop​

If your goal is simply to exit a loop prematurely, the correct keyword is break, not return.

let numbers = [1, 2, 3, 4, 5];

for (let num of numbers) {
  if (num > 3) {
    // Correct: `break` exits the loop.
    break;
  }
  console.log(num);
}
// Output: 1, 2, 3

Output:

1
2
3

Cause 3: A Syntax Error (like a Missing Curly Brace)​

Sometimes, you think your return statement is inside a function, but a simple syntax error, like a missing opening curly brace ({), makes the JavaScript parser see it as being in the global scope.

Example of problem:

// Problem: The opening curly brace for the function is missing.
function myFunc()
  let myValue = 10;
  return myValue; // The parser sees this as being outside any function.
}

Error Output:

Uncaught SyntaxError: Illegal return statement

Solution: this is a simple typo. Fix the syntax by adding the missing curly brace. Modern code editors with syntax highlighting (linters) will almost always catch this for you.

// Correct: Add the opening curly brace.
function myFunc() {
  let myValue = 10;
  return myValue;
}

Conclusion​

The SyntaxError: Illegal return statement error is a clear signal that the return keyword is being used in an invalid context.

To solve it:

  • Ensure your return statements are always inside a function.
  • If you need to exit a loop (like for or while), use the break keyword instead.
  • Check your code for syntax errors, like missing curly braces, that could be causing your return to be misinterpreted as being in the global scope.

Table of Contents