time-warp-manipulation/__tests__/demo.js

A TypeScript-based library for manipulating JavaScript time: freeze, fast-forward, rewind, or accelerate the clock.

import {
  enableTimeWarp,
  disableTimeWarp,
  setTimeWarpOptions,
  getVirtualTime,
} from "time-warp-manipulation";

/**
 * Example: Freeze time, then accelerate it, and finally restore real time.
 */

// Freeze time at Jan 1, 2030, 00:00:00 UTC
// The timestamp for Jan 1, 2030, 00:00:00 UTC is 1893456000000 ms since the Unix epoch.
enableTimeWarp({
  freezeAt: new Date("2030-01-01T00:00:00Z").getTime(),
  monkeyPatch: true, // This will replace the global Date with our TimeWarpDate
});

// Now, every call to Date.now() returns the frozen timestamp.
console.log("Frozen time:", Date.now()); // Expected output: 1893456000000

// After some operations, you may want to resume time flow.
// Here, we disable the freeze and set a speed factor to accelerate time.
// Setting freezeAt to null removes the freeze, and speed of 5 makes time pass 5 times faster.
setTimeWarpOptions({
  freezeAt: null,
  speed: 5,
});

// With acceleration enabled, 1 real second will simulate 5 seconds of "warped" time.
// You can use getVirtualTime() to retrieve the current virtual time without altering global Date if needed.
console.log("Accelerated virtual time:", getVirtualTime().now());

// When finished, restore the original Date object to return to normal behavior.
disableTimeWarp();
console.log("Real time restored:", Date.now());

// Should output something like:
// > node __tests__/demo.js
//
// [getWarpedTime] realNow: 1742156511323, startRealTime: 0, realElapsed: 1742156511323, speed: 1, startWarpTime: 0, warpedTime: 1742156511323
// [setTimeWarpOptions] Previous warped time: 1742156511323
// [setTimeWarpOptions] Set freezeAt to: 1893456000000
// [setTimeWarpOptions] Set speed to: 1
// [getWarpedTime] Time is frozen at: 1893456000000
// [setTimeWarpOptions] TimeWarp activated. startRealTime: 1742156511329 startWarpTime: 1893456000000
// [monkeyPatchGlobalDate] Monkey-patching global Date with TimeWarpDate.
// [getWarpedTime] Time is frozen at: 1893456000000
// [TimeWarpDate.now] Returning warped time: 1893456000000
// Frozen time: 1893456000000
// [getWarpedTime] Time is frozen at: 1893456000000
// [setTimeWarpOptions] Previous warped time: 1893456000000
// [setTimeWarpOptions] Set freezeAt to: null
// [setTimeWarpOptions] Set speed to: 5
// [getWarpedTime] realNow: 1742156511329, startRealTime: 1742156511329, realElapsed: 0, speed: 5, startWarpTime: 1893456000000, warpedTime: 1893456000000
// [setTimeWarpOptions] TimeWarp updated. New startRealTime: 1742156511329 New startWarpTime: 1893456000000
// [getVirtualTimeObject] Returning virtual time object.
// [getWarpedTime] realNow: 1742156511330, startRealTime: 1742156511329, realElapsed: 1, speed: 5, startWarpTime: 1893456000000, warpedTime: 1893456000005
// Accelerated virtual time: 1893456000005
// [disableTimeWarpCompletely] Disabling TimeWarp.
// [restoreGlobalDate] Restoring original Date class.
// Real time restored: 1742156511330