TypeError: invalid Array.prototype.sort argument

The JavaScript exception "invalid Array.prototype.sort argument" occurs when the argument of {{jsxref("Array.prototype.sort()")}} (and its related methods: {{jsxref("Array.prototype.toSorted()")}}, {{jsxref("TypedArray.prototype.sort()")}}, {{jsxref("TypedArray.prototype.toSorted()")}}) isn't either {{jsxref("undefined")}} or a function that compares its operands.

Message#

TypeError: The comparison function must be either a function or undefined (V8-based)

TypeError: invalid Array.prototype.sort argument (Firefox)
TypeError: non-function passed to Array.prototype.toSorted (Firefox)
TypeError: invalid %TypedArray%.prototype.sort argument (Firefox)

TypeError: Array.prototype.sort requires the comparator argument to be a function or undefined (Safari)
TypeError: Array.prototype.toSorted requires the comparator argument to be a function or undefined (Safari)
TypeError: TypedArray.prototype.sort requires the comparator argument to be a function or undefined (Safari)
TypeError: TypedArray.prototype.toSorted requires the comparator argument to be a function or undefined (Safari)

Error type#

{{jsxref("TypeError")}}

What went wrong?#

The argument of {{jsxref("Array.prototype.sort()")}} (and its related methods: {{jsxref("Array.prototype.toSorted()")}}, {{jsxref("TypedArray.prototype.sort()")}}, {{jsxref("TypedArray.prototype.toSorted()")}}) is expected to be either {{jsxref("undefined")}} or a function which compares its operands.

Examples#

Invalid cases#

```js example-bad [1, 3, 2].sort(5); // TypeError students.toSorted("name"); // TypeError

### Valid cases

```js example-good
[1, 3, 2].sort(); // [1, 2, 3]
[1, 3, 2].sort((a, b) => a - b); // [1, 2, 3]
students.toSorted((a, b) => a.name.localeCompare(b.name));

See also#

• {{jsxref("Array.prototype.sort()")}}
• {{jsxref("Array.prototype.toSorted()")}}
• {{jsxref("TypedArray.prototype.sort()")}}
• {{jsxref("TypedArray.prototype.toSorted()")}}