Snowflake IDs in Javascript (For 53bit)

snowflake.js

// 53 bits unique id: 41 bits for time in milliseconds + 12 bits for sequence number
class Snowflake {
    constructor(options) {
        options = options || {};
        this.seq = 0;
        this.offset = options.offset || 0; // 2019-04-01T00:00:00Z
        this.lastTime = 0;
    }

    generate() {
        const time = Date.now(),
            bTime = (time - this.offset).toString(2).padStart(41, '0'); // 41 Bits

        // get the sequence number
        if (this.lastTime == time) {
            this.seq++;

            if (this.seq > 4095) {
                this.seq = 0;
                // make system wait till time is been shifted by one millisecond
                while (Date.now() <= time) {}
            }
        } else {
            this.seq = 0;
        }

        this.lastTime = time;

        let bSeq = this.seq.toString(2).padStart(12, '0'); // 12 Bits

        const bid = bTime + bSeq;
        let id = "";

        id = BigInt('0b' + bid).toString();

        return id;
    }
}

module.exports = new Snowflake({
    offset: new Date('2019-04-01T00:00:00Z').getTime()
})