Multi tool use

Ensure promises are not leaked at the end of async function

I plan to use async/await to run many tasks. Since I can't afford to do await on the tasks because main loop will keep spawning new tasks, I need to ensure the promise for the task is destroyed at the end. Does the following code snippet has a leakage of of promises? If there is a better way to achieve this, please let me know too.

const fetch = require ('node-fetch')

var gId = 0;
var ps = {}

var lId = gId; gId ++;
ps[lId] = task(lId)
lId = gId; gId ++;
ps[lId] = task(lId)
//will add many more tasks


async function task(id) {
console.log("starting..")
var url = "http://localhost/prod/te.php";
var r1 = await fetch(url).then((r) => r.text())
console.log(new Date() + "|" + id)
await wait(parseInt(r1) * 1000)
var r2 = await fetch(url).then((r) => r.text())
console.log(new Date + "|" + id)
ps[id].then(() => console.log("deleted promise " + id))
delete ps[id]
}

async function wait(ms) {
return new Promise (function (resolve, reject) {
setTimeout(function() {
console.log("expired")
resolve(0)
}, ms)
})
}


ps

delete ps[id]

1 Answer
1

Did some tests and it comes down to, promises will not be leaked at all (which will cause memory leak as I feared). Ran the following code for a long time and the memory consumption on my Mac hovers around 100MB.

const fetch = require ('node-fetch')


var gId = 0;
start()
async function start() {
var lId;
var count = 0;
while (1) {
lId = gId; gId ++;
task(lId)
count ++;
if (count == 100) {
count = 0;
await wait(500)
}
}
}


async function task(id) {
var url = "http://localhost/prod/te.php";
var r1 = await fetch(url).then((r) => r.text())
await wait(parseInt(r1) * 1000)
var r2 = await fetch(url).then((r) => r.text())
}

async function wait(ms) {
return new Promise (function (resolve, reject) {
setTimeout(function() {
resolve(0)
}, ms)
})
}


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.