RangeError: BigInt negative exponent

The JavaScript exception "BigInt negative exponent" occurs when a {{jsxref("BigInt")}} is raised to the power of a negative BigInt value.

Message#

RangeError: Exponent must be positive (V8-based)
RangeError: BigInt negative exponent (Firefox)
RangeError: Negative exponent is not allowed (Safari)

Error type#

{{jsxref("RangeError")}}.

What went wrong?#

The exponent of an exponentiation operation must be positive. Since negative exponents would take the reciprocal of the base, the result will be between -1 and 1 in almost all cases, which gets rounded to 0n. To catch mistakes, negative exponents are not allowed. Check if the exponent is non-negative before doing exponentiation.

Examples#

Using a negative BigInt as exponent#

```js example-bad const a = 1n; const b = -1n; const c = a ** b; // RangeError: BigInt negative exponent

Instead, check if the exponent is negative first, and either issue an error with a better message, or fallback to a different value, like `0n` or `undefined`.

```js example-good
const a = 1n;
const b = -1n;
const quotient = b >= 0n ? a ** b : 0n;

See also#

• BigInt
• Exponentiation (**)