How to make a high-resolution setInterval in Node with It's possible in browser with just setInterval

I want to make an real-time application for working with serial on 250Hz speed For this I need to have clean intervals with duration below 5ms

function measure(setTimeout, time) {
    let i = 0, a = new Float64Array(10_000), p = Promise.withResolvers();
    let start = performance.now();
    let lastNow = start;
    function loop() {
        let now = performance.now();
        a[i++] = now - lastNow;
        if (now - start > time) {
            p.resolve(a.slice(1, i-1).sort().reverse())
        } else {
            lastNow = now;
            setTimeout(loop);
        }
    }
    loop();
    return p.promise;
}

Promise.withResolvers ??= (o={})=>Object.assign(o,{promise:new Promise((r,j)=>{o.resolve=r;o.reject=j})})

measure(f => setTimeout(f, 1), 1000).then(a => console.log({
   hz: a.length,
   max: a[0],
   '99%': a[~~(a.length*0.99)],
   '95%': a[~~(a.length*0.95)],
   '90%': a[~~(a.length*0.90)],
   median: a[~~()],
   a,
}))
// browser: {hz:216,max:6.3,99%:6.1,95:5.9,90:5.2,median:4.6} - fine
// node: {hz:69,max:16.3,99%:16.1,95:16,90:16.2,median:15.45} - I want better then this
// bun: {hz:61,max:32.3,99%:32.1,95:17.8,90:16.2,median:15.45} - I want better then this

How to make a high-resolution setInterval in Node with It's possible in browser with just setInterval

I want to make an real-time application for working with serial on 250Hz speed For this I need to have clean intervals with duration below 5ms

function measure(setTimeout, time) {
    let i = 0, a = new Float64Array(10_000), p = Promise.withResolvers();
    let start = performance.now();
    let lastNow = start;
    function loop() {
        let now = performance.now();
        a[i++] = now - lastNow;
        if (now - start > time) {
            p.resolve(a.slice(1, i-1).sort().reverse())
        } else {
            lastNow = now;
            setTimeout(loop);
        }
    }
    loop();
    return p.promise;
}

Promise.withResolvers ??= (o={})=>Object.assign(o,{promise:new Promise((r,j)=>{o.resolve=r;o.reject=j})})

measure(f => setTimeout(f, 1), 1000).then(a => console.log({
   hz: a.length,
   max: a[0],
   '99%': a[~~(a.length*0.99)],
   '95%': a[~~(a.length*0.95)],
   '90%': a[~~(a.length*0.90)],
   median: a[~~()],
   a,
}))
// browser: {hz:216,max:6.3,99%:6.1,95:5.9,90:5.2,median:4.6} - fine
// node: {hz:69,max:16.3,99%:16.1,95:16,90:16.2,median:15.45} - I want better then this
// bun: {hz:61,max:32.3,99%:32.1,95:17.8,90:16.2,median:15.45} - I want better then this

• javascript
• node.js
• setinterval
• bun
• high-resolution-time

1 Answer 1

You may get precise timeouts using setImmediate I'm not yet sure it won't be heavy on CPU time it's but at least it works

function setTimeoutPrecise(callback, time) {
  const start = performance.now()
  loop()
  function loop() {
    if (performance.now() - start >= time) {
      callback()
    }
    else {
      setImmediate(loop)
    }
  }
}

node: {
  hz: 985,
  max: 9.391000000000005,
  '99%': 1.0891000000000304,
  '95%': 1.011099999999999,
  '90%': 1.0066999999999666,
  median: 1.0028999999999542,
}
bun: {
  hz: 980,
  max: 4.150199999999998,
  "99%": 1.8109999999999218,
  "95%": 1.0130000000000052,
  "90%": 1.0060999999999964,
  median: 1.0013000000000147,
}