SyntaxError: 'arguments'/'eval' can't be defined or assigned to in strict mode code

The JavaScript strict mode-only exception "'arguments' can't be defined or assigned to in strict mode code" or "'eval' can't be defined or assigned to in strict mode code" occurs when attempting to create a {{Glossary("binding")}} called arguments or eval, or assign to such a name.

Message#

SyntaxError: Unexpected eval or arguments in strict mode (V8-based)
SyntaxError: 'arguments' can't be defined or assigned to in strict mode code (Firefox)
SyntaxError: Cannot modify 'arguments' in strict mode. (Safari)
SyntaxError: Cannot destructure to a parameter name 'arguments' in strict mode. (Safari)
SyntaxError: Cannot declare a variable named arguments in strict mode. (Safari)
SyntaxError: Cannot declare a catch variable named 'arguments' in strict mode. (Safari)
SyntaxError: 'arguments' is not a valid function name in strict mode. (Safari)

Error type#

{{jsxref("SyntaxError")}}

What went wrong?#

In strict mode, the names {{jsxref("Functions/arguments", "arguments")}} and {{jsxref("Global_Objects/eval", "eval")}} behave as if they are reserved words: you cannot make they refer to anything other than the arguments object in functions or the global eval function.

Examples#

Invalid cases#

```js example-bad "use strict";

const arguments = [1, 2, 3]; console.log(Math.max(...arguments));

function foo(...arguments) { console.log(arguments); }

### Valid cases

```js example-good
"use strict";

const args = [1, 2, 3];
console.log(Math.max(...args));

function foo(...args) {
  console.log(args);
}

See also#

• Strict mode
• {{jsxref("Functions/arguments", "arguments")}}
• {{jsxref("Global_Objects/eval", "eval()")}}