Small utility to convert times between GPS epoch (midnight January 6, 1980) and Unix epoch (midnight January 1, 1970), taking into account leap seconds.

It's not such a trivial matter as adding a constant number of leap seconds to all time inputs! For any two times, a different number of leap seconds may have elapsed between them. This utility helps figure out exactly how many have elapsed.

No dependencies! Very small: 464 bytes gzipped.

Works on the client and on the server (in Node.js).

npm i --save gps-time

AMD and CommonJS are supported, with a fallback that defines this utility at window.gpsTime

In Node, you can bring in this utility with this:

var gpsTime = require('gps-time');

var unixMS = Date.now();  // 1454168480000
gpsTime.toGPSMS(unixMS);  // 1138203697000

var gpsMS = 1138203697000;
gpsTime.toUnixMS(gpsMS);  // 1454168480000

This comes with a small test suite which can be run like this:

$ npm install --dev
$ npm test

Licenced under MIT