dynatrace-cordova-outsystems-plugin/node_modules/w3c-hr-time/lib/calculate-clock-offset.js

This plugin gives you the ability to use the Dynatrace instrumentation in your hybrid application (Cordova, Ionic, ..). It uses the Mobile Agent, the JavaScript Agent and the Javascript Bridge. The Mobile Agent will give you all device specific values con

"use strict";

// This files implements the calculation of the offset between the global monotonic clock and UNIX time. This value is
// known as |t1| in the calculation of "time origin timestamp" in the spec. This value needs to be calculated once and
// can be used in all subsequent Performance instances.
//
// However, if the clock is not fast enough, the export is undefined to signify that we should use Date.now() to get the
// time origin timestamp with millisecond accuracy, per spec.

const { getGlobalMonotonicClockMS } = require("./global-monotonic-clock");
const clockIsAccurate = require("./clock-is-accurate");

// This function assumes the clock is accurate.
function calculateClockOffset() {
  const start = Date.now();
  let cur = start;
  while (cur === start) {
    cur = Date.now();
  }

  // At this point |cur| "just" became equal to the next millisecond -- the unseen digits after |cur| are approximately
  // all 0, and |cur| is the closest to the actual value of the UNIX time. Now, get the current global monotonic clock
  // value and do the remaining calculations.

  return cur - getGlobalMonotonicClockMS();
}

if (clockIsAccurate) {
  // Warm up the function.
  calculateClockOffset();
  calculateClockOffset();
  calculateClockOffset();

  module.exports = calculateClockOffset;
} else {
  module.exports = undefined;
}