SyntaxError: invalid BigInt syntax

The JavaScript exception "invalid BigInt syntax" occurs when a string value is being coerced to a {{jsxref("BigInt")}} but it failed to be parsed as an integer.

Message#

SyntaxError: Cannot convert x to a BigInt (V8-based)
SyntaxError: invalid BigInt syntax (Firefox)
SyntaxError: Failed to parse String to BigInt (Safari)

Error type#

{{jsxref("SyntaxError")}}.

What went wrong?#

When using the BigInt() function to convert a string to a BigInt, the string will be parsed in the same way as source code, and the resulting value must be an integer value.

Examples#

Invalid cases#

```js example-bad const a = BigInt("1.5"); const b = BigInt("1n"); const c = BigInt.asIntN(4, "8n"); // SyntaxError: invalid BigInt syntax

### Valid cases

```js example-good
const a = BigInt("1");
const b = BigInt("  1   ");
const c = BigInt.asIntN(4, "8");

See also#

• BigInt