snowflake-uuid/dist/index.js

Twitter's Snowflake generator implementation for NodeJS

'use strict';
Object.defineProperty(exports, "__esModule", { value: true });
exports.Worker = void 0;
class Worker {
    #epoch;
    #workerId;
    #workerIdBits;
    #maxWorkerId;
    #datacenterId;
    #datacenterIdBits;
    #maxDatacenterId;
    #sequence;
    #sequenceBits;
    #workerIdShift;
    #datacenterIdShift;
    #timestampLeftShift;
    #sequenceMask;
    #lastTimestamp = -1n;
    constructor(workerId = 0n, datacenterId = 0n, options) {
        this.#epoch = BigInt(options?.epoch ?? 1609459200000);
        this.#workerId = BigInt(workerId);
        this.#workerIdBits = BigInt(options?.workerIdBits ?? 5);
        this.#maxWorkerId = -1n ^ (-1n << this.#workerIdBits);
        if (this.#workerId < 0 || this.#workerId > this.#maxWorkerId) {
            throw new Error('With ' +
                this.#workerIdBits.toString() +
                " bits, worker id can't be greater than " +
                this.#maxWorkerId.toString() +
                ' or less than 0');
        }
        this.#datacenterId = BigInt(datacenterId);
        this.#datacenterIdBits = BigInt(options?.datacenterIdBits ?? 5);
        this.#maxDatacenterId = -1n ^ (-1n << this.#datacenterIdBits);
        if (this.#datacenterId > this.#maxDatacenterId || this.#datacenterId < 0) {
            throw new Error('With ' +
                this.#datacenterIdBits.toString() +
                " bits, datacenter id can't be greater than " +
                this.#maxDatacenterId.toString() +
                ' or less than 0');
        }
        this.#sequence = BigInt(options?.sequence ?? 0);
        this.#sequenceBits = BigInt(options?.sequenceBits ?? 12);
        this.#sequenceMask = -1n ^ (-1n << this.#sequenceBits);
        this.#workerIdShift = this.#sequenceBits;
        this.#datacenterIdShift = this.#sequenceBits + this.#workerIdBits;
        this.#timestampLeftShift = this.#sequenceBits + this.#workerIdBits + this.#datacenterIdBits;
    }
    get workerId() {
        return this.#workerId;
    }
    get datacenterId() {
        return this.#datacenterId;
    }
    get currentSequence() {
        return this.#sequence;
    }
    get lastTimestamp() {
        return this.#lastTimestamp;
    }
    nextId() {
        let timestamp = Worker.now();
        if (timestamp < this.#lastTimestamp) {
            throw new Error("Clock moved backwards. Can't generate new ID for " +
                (this.#lastTimestamp - timestamp).toString() +
                'milliseconds.');
        }
        if (timestamp === this.#lastTimestamp) {
            this.#sequence = (this.#sequence + 1n) & this.#sequenceMask;
            if (this.#sequence === 0n) {
                timestamp = this.tilNextMillis(this.#lastTimestamp);
            }
        }
        else {
            this.#sequence = 0n;
        }
        this.#lastTimestamp = timestamp;
        return (((timestamp - this.#epoch) << this.#timestampLeftShift) |
            (this.#datacenterId << this.#datacenterIdShift) |
            (this.#workerId << this.#workerIdShift) |
            this.#sequence);
    }
    tilNextMillis(lastTimestamp) {
        let timestamp;
        do {
            timestamp = Worker.now();
        } while (timestamp <= lastTimestamp);
        return timestamp;
    }
    static now() {
        return BigInt(Date.now());
    }
}
exports.Worker = Worker;