Node.JS module to fetch the current time from NTP servers and returns offset information.
ℹ️ NTP requires UDP which is not available in a browser context!
# using Yarn$ yarn add ntp-time-sync# using NPM$ npm install ntp-time-sync
Consider using the library as a singleton, so that not every call togetTime fires new NTP packages.The library itself will manage minimum/maximum poll times.
Several requests to multiple NTP time servers are fired and the responses will be aggregated.
// ES6:import{NtpTimeSync}from"ntp-time-sync";// pre-ES6:// const NtpTimeSync = require("ntp-time-sync").NtpTimeSync;consttimeSync=NtpTimeSync.getInstance();// request 1timeSync.getTime().then(function(result){console.log("current system time",newDate());console.log("real time",result.now);console.log("offset in milliseconds",result.offset);})// request 2, will use cached offset from previous requesttimeSync.getTime().then(function(result){console.log("current system time",newDate());console.log("real time",result.now);console.log("offset in milliseconds",result.offset);})// ES2017 styleconstresult=awaittimeSync.getTime();console.log("real time",result.now);<ntpTimeSyncInstance>.getTime() returns aPromise object which will eventually be resolved with a object containing the following information:
| Property | Description |
|---|
now | Current NTP time ("real time") |
offset | Calculated offset between local system time and NTP time |
<ntpTimeSyncInstance>.now() returns aDate object containing the correct time for the moment when the function was called.In contrast togetTime(), which will return the correct time for the moment the Promise gets resolved.
You can pass custom options to the constructor ofNtpTimeSync orNtpTimeSync.getInstance(options).These will be merged with the following defaults:
constdefaultOptions={// list of NTP time servers, optionally including a port (defaults to 123)servers:["0.pool.ntp.org","1.pool.ntp.org","2.pool.ntp.org","3.pool.ntp.org"],// required amount of valid samples in order to calculate the timesampleCount:8,// amount of time in milliseconds to wait for a single NTP responsereplyTimeout:3000,// defaults as of RFC5905ntpDefaults:{port:123,version:4,tolerance:15e-6,minPoll:4,maxPoll:17,maxDispersion:16,minDispersion:0.005,maxDistance:1,maxStratum:16,precision:-18,referenceDate:newDate("Jan 01 1900 GMT")}};