- Version: 8.4.0
- Platform: Windows 7 x64
- Subsystem: libuv, promises
Revisiting this article, I've found out that an example which illustrates some known bug (?) in microtask queue execution behaves differently because of times of script call.
'use strict';
console.log('script start')
const interval = setInterval(() => {
console.log('setInterval')
}, 0)
setTimeout(() => {
console.log('setTimeout 1')
Promise.resolve().then(() => {
console.log('promise 3')
}).then(() => {
console.log('promise 4')
}).then(() => {
setTimeout(() => {
console.log('setTimeout 2') //< place of random microtask queue intrusion
Promise.resolve().then(() => {
console.log('promise 5')
}).then(() => {
console.log('promise 6')
}).then(() => {
clearInterval(interval)
})
}, 0)
})
}, 0)
Promise.resolve().then(() => {
console.log('promise 1')
}).then(() => {
console.log('promise 2')
})Every first call in a new cmd.exe terminal produces the mentioned error. Every next call has proper execution order:
>node test.js
script start
promise 1
promise 2
setInterval
setTimeout 1
promise 3
promise 4
setInterval
setTimeout 2
setInterval //< intruder
promise 5
promise 6
>node test.js
script start
promise 1
promise 2
setInterval
setTimeout 1
promise 3
promise 4
setInterval
setTimeout 2
promise 5
promise 6
Compare the next step after the setTimeout 2 output.
Revisiting this article, I've found out that an example which illustrates some known bug (?) in microtask queue execution behaves differently because of times of script call.
Every first call in a new
cmd.exeterminal produces the mentioned error. Every next call has proper execution order:Compare the next step after the
setTimeout 2output.