TypeError: invalid Array.prototype.sort argument

The JavaScript exception "invalid Array.prototype.sort argument" occurs when the argument of Array.prototype.sort() isn't either undefined or a function which 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: Array.prototype.sort requires the comparator argument to be a function or undefined (Safari)

Error type

TypeError

What went wrong?

The argument of Array.prototype.sort() is expected to be either undefined or a function which compares its operands.

Examples

Invalid cases

[1, 3, 2].sort(5); // TypeError

const cmp = { asc: (x, y) => x >= y, dsc: (x, y) => x <= y };
[1, 3, 2].sort(cmp[this.key] || "asc"); // TypeError

Valid cases

[1, 3, 2].sort(); // [1, 2, 3]

const cmp = { asc: (x, y) => x >= y, dsc: (x, y) => x <= y };
[1, 3, 2].sort(cmp[this.key || "asc"]); // [1, 2, 3]