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
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.
const a = 1n;
const b = -1n;
const quotient = b >= 0n ? a ** b : 0n;