I am developing test nodejs app, I want to create 100 "threads", each executed at some random time using setTimeOut.
let count = 10;
let counter = 0;
for(let i = 0; i < count; i++) {
// call the rest of the code and have it execute after 3 seconds
setTimeout((async () => {
counter++;
console.log('executed thread',i, 'current counter is',counter);
if(counter === count){
console.log('all processed');
}
}), Math.random()*10);
console.log('executed setTimeOut number ',i);
}
console.log('main thread done, awaiting async');
Now what I dont understand is output:
executed setTimeOut number 0
executed setTimeOut number 1
executed setTimeOut number 2
executed setTimeOut number 3
executed setTimeOut number 4
executed setTimeOut number 5
executed setTimeOut number 6
executed setTimeOut number 7
executed setTimeOut number 8
executed setTimeOut number 9
main thread done, awaiting async
executed thread 5 current counter is 1
executed thread 1 current counter is 2
executed thread 4 current counter is 3
executed thread 9 current counter is 4
executed thread 6 current counter is 5
executed thread 2 current counter is 6
executed thread 3 current counter is 7
executed thread 8 current counter is 8
executed thread 0 current counter is 9
executed thread 7 current counter is 10
all processed
What I would expect is mixed executed thread X current counter is Y between the executed setTimeOut number Z, why does it first seem to add all calls into setTimeOut and only after that execute them? Even when I set count to 1,000,000 this is still happening. That does not look like an expected behavior to me.
