karatelabs/karate · error · JsErrorException

Cannot convert non-finite number to BigInt

Error message

Cannot convert non-finite number to BigInt

What it means

Spec ToBigInt rejects numbers that are not finite integers. Karate's primitiveToBigInt throws RangeError 'Cannot convert non-finite number to BigInt' for Infinity, -Infinity, and NaN, and a sibling RangeError for non-integer finite numbers.

Solutions

1. Check Number.isFinite(v) before BigInt(v)
2. Round or validate integrality: Number.isInteger(v) || Math.round(v)
3. Fix upstream math that produced Infinity/NaN (division by zero, failed parse)
4. Parse strings directly: BigInt('123') instead of going through float

Example fix

// before
const n = BigInt(total / count); // Infinity when count === 0
// after
if (!Number.isFinite(total / count) || !Number.isInteger(total / count)) throw new Error('bad input');
const n = BigInt(Math.trunc(total / count));

if (typeof v === 'number' && (!Number.isFinite(v) || !Number.isInteger(v))) throw new Error('BigInt needs a finite integer, got ' + v);

function isSafeBigIntSource(x) { return typeof x === 'bigint' || (typeof x === 'number' && Number.isFinite(x) && Number.isInteger(x)) || (typeof x === 'string' && /^-?\d+$/.test(x)); }

try { return BigInt(v); } catch (e) { if (String(e.message).includes('non-finite') || String(e.message).includes('non-integer')) return 0n; throw e; }

When it happens

Trigger: BigInt(Infinity); BigInt(-Infinity); BigInt(NaN); BigInt(1.5) (non-integer variant); dividing by zero or parsing failing before a BigInt conversion.

Common situations: Division results that became Infinity (x/0 in JS), parseFloat on malformed strings yielding NaN, averaging routines producing non-integers, JSON payloads with non-numeric sentinels.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Cannot convert non-integer number to BigInt
• ToIndex: value must be non-negative
• toString() radix must be between 2 and 36
• Cannot convert a BigInt to a number using unary +
• array index too large for dense storage:

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/087866a4a3568523. Report an issue: GitHub.

Appendix: source

Thrown at karate-js/src/main/java/io/karatelabs/js/JsBigIntConstructor.java:94

    // No-context overload for code paths that have only a primitive in hand
    // (e.g. asIntN/asUintN second arg already coerced). Matches spec when the
    // input is guaranteed primitive.
    static BigInteger toBigInt(Object value) {
        return toBigInt(value, null);
    }

    private static BigInteger primitiveToBigInt(Object value) {
        if (value instanceof BigInteger bi) {
            return bi;
        }
        if (value instanceof Boolean b) {
            return b ? BigInteger.ONE : BigInteger.ZERO;
        }
        if (value instanceof Number n) {
            double d = n.doubleValue();
            if (!Double.isFinite(d)) {
                throw JsErrorException.rangeError("Cannot convert non-finite number to BigInt");
            }
            if (d != Math.floor(d)) {
                throw JsErrorException.rangeError("Cannot convert non-integer number to BigInt");
            }
            return new BigDecimal(d).toBigInteger();
        }
        if (value instanceof String s) {
            String trimmed = s.trim();
            if (trimmed.isEmpty()) {
                return BigInteger.ZERO;
            }
            try {
                if (trimmed.length() > 2 && trimmed.charAt(0) == '0') {
                    char c = trimmed.charAt(1);
                    if (c == 'x' || c == 'X') return new BigInteger(trimmed.substring(2), 16);
                    if (c == 'o' || c == 'O') return new BigInteger(trimmed.substring(2), 8);
                    if (c == 'b' || c == 'B') return new BigInteger(trimmed.substring(2), 2);
                }

View on GitHub (pinned to a22eb90246)