virtual-time

Fast forward the event loop when it runs out of work

When installed, this library overwrites setTimeout, clearTimeout, setInterval, clearInterval and Date functionality. It will fast forward the timers on the event loop whenever it is idle.

Example

const virtualTime = require('virtual-time');
let realNow = Date.now;
virtualTime.install();

let startTimeReal = realNow();
let startTimeVirtual = Date.now();

setTimeout(() => {
  let durationReal = realNow() - startTimeReal;
  let durationVirtual = Date.now() - startTimeVirtual;
  console.log(`Real duration: ${durationReal}ms; Virtual duration: ${durationVirtual}ms`);
  // Real duration: 2ms; Virtual duration: 100000ms
}, 100000);

API

.install( [Object options] )

This will install the library.

options

number time

Default 0. The time in milliseconds of when the clock starts.

boolean addExecutionTime

Default true. This option makes it so execution time is calculated in the Date.now() call. Disable this option if you need deterministic Date.now() behavior.

.uninstall()

This will restore the timer functions to their normal state.