Why is setTimeout always earlier than setImmediate?

setImmediate(function A() {
    console.log("2")
})
setTimeout(function B() {
    console.log("1")
}, 0)

judging from online articles, setImmediate is supposed to be faster in theory (in front of the task queue), but this is not the case in practice. (Node 9.x)

Node.js
Mar.18,2021

did an experiment and ran it a few more times with node, and found that the order of execution is uncertain, but in most cases, setTimeout is faster. 

var recordA = {};
var recordB = {};
var MAX = 100;

function output(index) {
  if (index === MAX) {
    console.log('setImmediate:' + Object.keys(recordA).length);
    console.log('setTimeout:  ' + Object.keys(recordB).length);
  }
}

for (var i = 0; i <= MAX; PPi) {
  (function (_i) {
    setImmediate(function A() {
      if (!recordB.hasOwnProperty(_i)) {
        recordA[_i] = 'done';
        output(_i);
      }
    });

    setTimeout(function B() {
      if (!recordA.hasOwnProperty(_i)) {
        recordB[_i] = 'done';
        output(_i);
      }
    }, 0);
  })(i);
}

node version 9.2.0

then this setImmediate currently has only IE in the browser for self-amusement.

Previous: How to close eslint in electron

Next: Check selenium does not return content

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
© 2021 CodesHelper
Advertising Contact us About us
Menu