fake-current-time

Manipulate current time in your application for development and staging environments.

Uses Proxy and AsyncLocalStorage to isolate time contexts per request, allowing multiple users to test with different time offsets simultaneously.

Installation

``bash
npm install fake-current-time
`

Usage

This example shows integration with React Router framework mode. The key concept is:

- Server: Parse offset from cookie and wrap request handling with runner.run(offset, ...)
- Client: Call setup() to initialize time manipulation
- UI: Use setOffset() and clearOffset() to control time via cookie

$3

`typescript
import express from "express";
import { createRequestHandler } from "@react-router/express";
import { setup, parseOffsetFromCookie } from "fake-current-time/node";

const app = express();

// Do NOT setup in production
const runner = process.env.STAGE !== "production" ? setup() : null;

app.all(
"*",
(req, _, next) => {
const offset = runner
? parseOffsetFromCookie(req.headers.cookie || "")
: undefined;

return offset && runner ? runner.run(offset, next) : next();
},
createRequestHandler({
// ...
}),
);
`

$3

`typescript
import { startTransition } from "react";
import { setup } from "fake-current-time/browser";

// Do NOT setup in production
if (process.env.STAGE !== "production") {
setup();
}

startTransition(() => {
// ...
});
`

$3

`typescript
import { FakeTimeController } from "fake-current-time/react";

// Restrict access to this page in production (e.g., via routing or middleware)
export function TimeControlPage() {
return ;
}
`

!FakeTimeController UI

$3

If you need to access the real Date while time manipulation is active, use OriginalDate:

`typescript
import { OriginalDate } from "fake-current-time";

const realNow = OriginalDate.now();
const realDate = new OriginalDate();
``