import { isBigInt } from "https://deno.land/x/unknownutil@v3.18.0/is.ts";
Return true if the type of x is bigint.
import { is } from "@core/unknownutil";
const a: unknown = 0n;
if (is.BigInt(a)) {
// a is narrowed to bigint
const _: bigint = a;
}