How to get a microtime in Node.js?

The BigInt data type is supported since Node.js 10.7.0. (see also the blog post announcement). For these supported versions of Node.js, the process.hrtime([time]) method is now regarded as 'legacy', replaced by the process.hrtime.bigint() method.

The bigint version of the process.hrtime() method returning the current high-resolution real time in a bigint.

const start = process.hrtime.bigint();
// 191051479007711n

setTimeout(() => {
  const end = process.hrtime.bigint();
  // 191052633396993n

  console.log(`Benchmark took ${end - start} nanoseconds`);
  // Benchmark took 1154389282 nanoseconds
}, 1000);

tl;dr

• Node.js 10.7.0+ - Use process.hrtime.bigint()
• Otherwise - Use process.hrtime()

You can also use performance API that works both in NodeJS and Browser:

var start = performance.timing ?
    performance.timing.navigationStart :
    performance.timeOrigin;

var time = (performance.now() + start) * 1000;

The Performance API stores value in floating-point number and the fraction is microseconds.

I'm not so proud about this solution but you can have timestamp in microsecond or nanosecond in this way:

const microsecond = () => Number(Date.now() + String(process.hrtime()[1]).slice(3,6))
const nanosecond = () => Number(Date.now() + String(process.hrtime()[1]).slice(3))

// usage
microsecond() // return 1586878008997591
nanosecond()  // return 1586878009000645600

// Benchmark with 100 000 iterations
// Date.now: 7.758ms
// microsecond: 33.382ms
// nanosecond: 31.252ms

Know that:

• This solution works exclusively with node.js,
• This is about 3 to 10 times slower than Date.now()
• Weirdly, it seems very accurate, hrTime seems to follow exactly js timestamp ticks.
• You can replace Date.now() by Number(new Date()) to get timestamp in milliseconds

Edit:

Here a solution to have microsecond with comma, however, the number version will be rounded natively by javascript. So if you want the same format every time, you should use the String version of it.

const microsecondWithCommaString = () => (Date.now() + '.' + String(process.hrtime()[1]).slice(3,7))
const microsecondWithComma = () => Number(Date.now() + '.' + String(process.hrtime()[1]).slice(3,7))

microsecondWithCommaString() // return "1586883629984.8997"
microsecondWithComma() // return 1586883629985.966

A rewrite to help quick understanding:

const hrtime = process.hrtime();     // [0] is seconds, [1] is nanoseconds

let nanoSeconds = (hrtime[0] * 1e9) + hrtime[1];    // 1 second is 1e9 nano seconds
console.log('nanoSeconds:  ' + nanoSeconds);
//nanoSeconds:  97760957504895

let microSeconds = parseInt(((hrtime[0] * 1e6) + (hrtime[1]) * 1e-3));
console.log('microSeconds: ' + microSeconds);
//microSeconds: 97760957504

let milliSeconds = parseInt(((hrtime[0] * 1e3) + (hrtime[1]) * 1e-6));
console.log('milliSeconds: ' + milliSeconds);
//milliSeconds: 97760957

Source: https://nodejs.org/api/process.html#process_process_hrtime_time

Get hrtime as single number in one line:

const begin = process.hrtime();
// ... Do the thing you want to measure
const nanoSeconds = process.hrtime(begin).reduce((sec, nano) => sec * 1e9 + nano)

Array.reduce, when given a single argument, will use the array's first element as the initial accumulator value. One could use 0 as the initial value and this would work as well, but why do the extra * 0.

The only way nowdays is call some 3rd party.

1. A lib with compiled function written on C (does't matter language, the point is OS syscall). Write your own or use for example https://www.npmjs.com/package/microtime (src https://github.com/wadey/node-microtime/blob/master/src/microtime.cc)
2. Spawn a process with date +%s%N, works on Linux out of box. Possible by using require('child_process').exec. I have no idea how accurate time would be because of performance of this solution

Note: process.hrtime is not about current time,

These times are relative to an arbitrary time in the past, and not related to the time of day. [https://www.geeksforgeeks.org/node-js-process-hrtime-method/]

process.hrtime() not give current ts.

This should work.

 const loadNs       = process.hrtime(),
        loadMs       = new Date().getTime(),
        diffNs       = process.hrtime(loadNs),
        microSeconds = (loadMs * 1e6) + (diffNs[0] * 1e9) + diffNs[1]

  console.log(microSeconds / 1e3)