snowflakeid-producer/test/snowflake.test.js

A simple and fast unique id generator for node.js. It generates unique id based on twitter's snowflake algorithm.

'use strict'

const os = require('os')
const test = require('node:test')
const assert = require('node:assert/strict')

// index.js builds a default generator with machineId=null, which reads network
// interfaces; stub so tests run in CI/sandboxes where os.networkInterfaces() fails.
const stubIfaces = {
  eth0: [
    { family: 'IPv4', internal: false, mac: '02:00:00:00:00:01', address: '10.0.0.2' },
  ],
}
const realNetworkInterfaces = os.networkInterfaces
os.networkInterfaces = () => stubIfaces
const { SnowflakeId, CustomSnowflakeId } = require('..')
os.networkInterfaces = realNetworkInterfaces

test('SnowflakeId.newId returns a numeric string', () => {
  const id = SnowflakeId.newId()
  assert.match(id, /^\d+$/)
})

test('SnowflakeId consecutive ids are unique', () => {
  const a = SnowflakeId.newId()
  const b = SnowflakeId.newId()
  assert.notEqual(a, b)
})

test('SnowflakeId.parseId round-trips newId', () => {
  const id = SnowflakeId.newId()
  const parsed = SnowflakeId.parseId(id)
  assert.ok(parsed.timestamp instanceof Date)
  assert.equal(typeof parsed.machineId, 'number')
  assert.equal(typeof parsed.sequence, 'number')
})

test('SnowflakeId getFirstIdAt / getLastIdAt for a fixed UTC instant', () => {
  const ts = Date.UTC(2025, 0, 15, 12, 0, 0)
  const first = SnowflakeId.getFirstIdAt(ts)
  const last = SnowflakeId.getLastIdAt(ts)
  assert.match(first, /^\d+$/)
  assert.match(last, /^\d+$/)
  assert(BigInt(last) >= BigInt(first))
})

test('CustomSnowflakeId with explicit machine id produces ids', () => {
  const gen = new CustomSnowflakeId({
    MachineIdBits: 10,
    SequenceBits: 12,
    MachineId: 7,
    FirstTimestamp: new Date('2024-01-01T00:00:00.000Z'),
  })
  const id = gen.newId()
  assert.match(id, /^\d+$/)
  const parsed = gen.parseId(id)
  assert.equal(parsed.machineId, 7)
})