Convert a BigInt to a base-64 number representation where the digits include (in the ascending order of value): 0-9, a-z, A-Z, &, and #

bigIntToBase64.js

function bigIntToBase64(value) {
	const base = 64n;
	const digits = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ&#";
	const sign = value < 0n ? "-" : "";
	let [result, quotient] = ["", sign ? 0n - this : this];
	do {
		result = `${digits[Number(quotient % base)]}${result}`;
	} while (quotient /= base);
	return `${sign}${result}`;
}