lanyard-profile-readme/src/snowflake.ts

interface DeconstructedSnowflake {
	timestamp: number;
	date: Date;
	workerID: number;
	processID: number;
	increment: number;
	binary: string;
}

const EPOCH = 1420070400000; // Discord's EPOCH

export function isSnowflake(snowflake: string): boolean {
	const { timestamp } = deconstruct(snowflake);
	if (timestamp > EPOCH && timestamp <= 3619093655551) {
		return true;
	}
	return false;
}

function deconstruct(snowflake: string): DeconstructedSnowflake {
	const BINARY = idToBinary(snowflake).padStart(64, "0");
	return {
		timestamp: parseInt(BINARY.substring(0, 42), 2) + EPOCH,
		get date() {
			return new Date(this.timestamp);
		},
		workerID: parseInt(BINARY.substring(42, 47), 2),
		processID: parseInt(BINARY.substring(47, 52), 2),
		increment: parseInt(BINARY.substring(52, 64), 2),
		binary: BINARY,
	};
}

function idToBinary(snowflake: string): string {
	let bin = "";
	let high = parseInt(snowflake.slice(0, -10)) || 0;
	let low = parseInt(snowflake.slice(-10));
	while (low > 0 || high > 0) {
		bin = String(low & 1) + bin;
		low = Math.floor(low / 2);
		if (high > 0) {
			low += 5000000000 * (high % 2);
			high = Math.floor(high / 2);
		}
	}
	return bin;
}