Can't get returned value from an 'async' function - Javascript
I am working with some asynchronous functions in javascript, but I am facing a problem, that I already posted here but that was a bit unpractical experience for everyone. Now, I made a simple constructor function with same member functions inside and returned a value, but seems like same problem to me, I tried my best but I don't know what is the problem, if you run this code then You can check what I want. Here's the demo link on JSfiddle, where you can see the results on console.
This is my Code
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
waitMore();
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})
When you comment out the conditions within the
setTimeout()and simplyres({page_job_details:"khan"});then you'll get the results in thenew Test().init().then(function(res){ console.log(res); }). Otherwise not, and that's the main problem.
javascript
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
add a comment |
I am working with some asynchronous functions in javascript, but I am facing a problem, that I already posted here but that was a bit unpractical experience for everyone. Now, I made a simple constructor function with same member functions inside and returned a value, but seems like same problem to me, I tried my best but I don't know what is the problem, if you run this code then You can check what I want. Here's the demo link on JSfiddle, where you can see the results on console.
This is my Code
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
waitMore();
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})
When you comment out the conditions within the
setTimeout()and simplyres({page_job_details:"khan"});then you'll get the results in thenew Test().init().then(function(res){ console.log(res); }). Otherwise not, and that's the main problem.
javascript
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
Thanks, can you explain what sort of output you were expecting instead?
– CertainPerformance
Nov 23 '18 at 6:17
@CertainPerformance I am expecting the answer in theres, when theTest().init()is called.
– Nadeem Ahmad
Nov 23 '18 at 6:18
You're receiving "khan" at the end of the promise, is not what you want?
– Miguel Angel
Nov 23 '18 at 6:20
@MiguelAngel It's not being chained to the end.init().thensection
– CertainPerformance
Nov 23 '18 at 6:22
I want the results returned by theinit()@MiguelAngel
– Nadeem Ahmad
Nov 23 '18 at 6:22
add a comment |
I am working with some asynchronous functions in javascript, but I am facing a problem, that I already posted here but that was a bit unpractical experience for everyone. Now, I made a simple constructor function with same member functions inside and returned a value, but seems like same problem to me, I tried my best but I don't know what is the problem, if you run this code then You can check what I want. Here's the demo link on JSfiddle, where you can see the results on console.
This is my Code
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
waitMore();
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})
When you comment out the conditions within the
setTimeout()and simplyres({page_job_details:"khan"});then you'll get the results in thenew Test().init().then(function(res){ console.log(res); }). Otherwise not, and that's the main problem.
javascript
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
I am working with some asynchronous functions in javascript, but I am facing a problem, that I already posted here but that was a bit unpractical experience for everyone. Now, I made a simple constructor function with same member functions inside and returned a value, but seems like same problem to me, I tried my best but I don't know what is the problem, if you run this code then You can check what I want. Here's the demo link on JSfiddle, where you can see the results on console.
This is my Code
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
waitMore();
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})
When you comment out the conditions within the
setTimeout()and simplyres({page_job_details:"khan"});then you'll get the results in thenew Test().init().then(function(res){ console.log(res); }). Otherwise not, and that's the main problem.
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
waitMore();
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
waitMore();
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})javascript
javascript
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
edited Nov 23 '18 at 6:21
Nadeem Ahmad
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
asked Nov 23 '18 at 6:15
Nadeem AhmadNadeem Ahmad
888
888
Thanks, can you explain what sort of output you were expecting instead?
– CertainPerformance
Nov 23 '18 at 6:17
@CertainPerformance I am expecting the answer in theres, when theTest().init()is called.
– Nadeem Ahmad
Nov 23 '18 at 6:18
You're receiving "khan" at the end of the promise, is not what you want?
– Miguel Angel
Nov 23 '18 at 6:20
@MiguelAngel It's not being chained to the end.init().thensection
– CertainPerformance
Nov 23 '18 at 6:22
I want the results returned by theinit()@MiguelAngel
– Nadeem Ahmad
Nov 23 '18 at 6:22
add a comment |
Thanks, can you explain what sort of output you were expecting instead?
– CertainPerformance
Nov 23 '18 at 6:17
@CertainPerformance I am expecting the answer in theres, when theTest().init()is called.
– Nadeem Ahmad
Nov 23 '18 at 6:18
You're receiving "khan" at the end of the promise, is not what you want?
– Miguel Angel
Nov 23 '18 at 6:20
@MiguelAngel It's not being chained to the end.init().thensection
– CertainPerformance
Nov 23 '18 at 6:22
I want the results returned by theinit()@MiguelAngel
– Nadeem Ahmad
Nov 23 '18 at 6:22
Thanks, can you explain what sort of output you were expecting instead?
– CertainPerformance
Nov 23 '18 at 6:17
Thanks, can you explain what sort of output you were expecting instead?
– CertainPerformance
Nov 23 '18 at 6:17
@CertainPerformance I am expecting the answer in the
res, when the Test().init() is called.– Nadeem Ahmad
Nov 23 '18 at 6:18
@CertainPerformance I am expecting the answer in the
res, when the Test().init() is called.– Nadeem Ahmad
Nov 23 '18 at 6:18
You're receiving "khan" at the end of the promise, is not what you want?
– Miguel Angel
Nov 23 '18 at 6:20
You're receiving "khan" at the end of the promise, is not what you want?
– Miguel Angel
Nov 23 '18 at 6:20
@MiguelAngel It's not being chained to the end
.init().then section– CertainPerformance
Nov 23 '18 at 6:22
@MiguelAngel It's not being chained to the end
.init().then section– CertainPerformance
Nov 23 '18 at 6:22
I want the results returned by the
init() @MiguelAngel– Nadeem Ahmad
Nov 23 '18 at 6:22
I want the results returned by the
init() @MiguelAngel– Nadeem Ahmad
Nov 23 '18 at 6:22
add a comment |
2 Answers
2
active
oldest
votes
One of the issues is that you are not returning the result of the recursive call from within the promise.
Instead of just calling it recursively
waitMore();
you seem to expect the result of the recursive call to be returned down the pipeline
res(waitMore());
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
Perfect Results, can you explain it a bit to me technically; why the results ofconsole.log("Response is : " + res.page_job_details);is three times displayed ? in theelsepart .
– Nadeem Ahmad
Nov 23 '18 at 6:31
1
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
add a comment |
There are two issues:
Inside
waitMore'ssetTimeout,resis only called ifcount === 2. Otherwise, the created promise never resolves, and whatever might beawaitingwaitMore()will never resolve - instead, that thread will remain suspended forever. You can fix this by callingresregardless of whethercountis2or not - if thecountis less than2, callreswith another invocation ofwaitMore:
res(waitMore());
On the level of the
this.initfunction, in the case that you need to wait more, you need toawait waitMore()(and put the response in a new variable that gets returned) so as to chain the Promise properly:
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
}
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
One of the issues is that you are not returning the result of the recursive call from within the promise.
Instead of just calling it recursively
waitMore();
you seem to expect the result of the recursive call to be returned down the pipeline
res(waitMore());
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
Perfect Results, can you explain it a bit to me technically; why the results ofconsole.log("Response is : " + res.page_job_details);is three times displayed ? in theelsepart .
– Nadeem Ahmad
Nov 23 '18 at 6:31
1
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
add a comment |
One of the issues is that you are not returning the result of the recursive call from within the promise.
Instead of just calling it recursively
waitMore();
you seem to expect the result of the recursive call to be returned down the pipeline
res(waitMore());
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
Perfect Results, can you explain it a bit to me technically; why the results ofconsole.log("Response is : " + res.page_job_details);is three times displayed ? in theelsepart .
– Nadeem Ahmad
Nov 23 '18 at 6:31
1
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
add a comment |
One of the issues is that you are not returning the result of the recursive call from within the promise.
Instead of just calling it recursively
waitMore();
you seem to expect the result of the recursive call to be returned down the pipeline
res(waitMore());
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
One of the issues is that you are not returning the result of the recursive call from within the promise.
Instead of just calling it recursively
waitMore();
you seem to expect the result of the recursive call to be returned down the pipeline
res(waitMore());
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
let p = new Promise(function(res, rej) {
setTimeout(async function() {
if (count === 2) {
res({
page_job_details: "khan"
});
} else {
count++;
res(waitMore());
}
}, 2000);
});
var res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
waitMore();
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
return khan;
}
}
new Test().init().then(function(res) {
console.log(res);
})answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
answered Nov 23 '18 at 6:27
Wiktor ZychlaWiktor Zychla
39.6k55680
39.6k55680
Perfect Results, can you explain it a bit to me technically; why the results ofconsole.log("Response is : " + res.page_job_details);is three times displayed ? in theelsepart .
– Nadeem Ahmad
Nov 23 '18 at 6:31
1
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
add a comment |
Perfect Results, can you explain it a bit to me technically; why the results ofconsole.log("Response is : " + res.page_job_details);is three times displayed ? in theelsepart .
– Nadeem Ahmad
Nov 23 '18 at 6:31
1
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
Perfect Results, can you explain it a bit to me technically; why the results of
console.log("Response is : " + res.page_job_details); is three times displayed ? in the else part .– Nadeem Ahmad
Nov 23 '18 at 6:31
Perfect Results, can you explain it a bit to me technically; why the results of
console.log("Response is : " + res.page_job_details); is three times displayed ? in the else part .– Nadeem Ahmad
Nov 23 '18 at 6:31
1
1
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
Three seems to be the level of your recursion.
– Wiktor Zychla
Nov 23 '18 at 6:33
add a comment |
There are two issues:
Inside
waitMore'ssetTimeout,resis only called ifcount === 2. Otherwise, the created promise never resolves, and whatever might beawaitingwaitMore()will never resolve - instead, that thread will remain suspended forever. You can fix this by callingresregardless of whethercountis2or not - if thecountis less than2, callreswith another invocation ofwaitMore:
res(waitMore());
On the level of the
this.initfunction, in the case that you need to wait more, you need toawait waitMore()(and put the response in a new variable that gets returned) so as to chain the Promise properly:
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
}
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
add a comment |
There are two issues:
Inside
waitMore'ssetTimeout,resis only called ifcount === 2. Otherwise, the created promise never resolves, and whatever might beawaitingwaitMore()will never resolve - instead, that thread will remain suspended forever. You can fix this by callingresregardless of whethercountis2or not - if thecountis less than2, callreswith another invocation ofwaitMore:
res(waitMore());
On the level of the
this.initfunction, in the case that you need to wait more, you need toawait waitMore()(and put the response in a new variable that gets returned) so as to chain the Promise properly:
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
}
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
add a comment |
There are two issues:
Inside
waitMore'ssetTimeout,resis only called ifcount === 2. Otherwise, the created promise never resolves, and whatever might beawaitingwaitMore()will never resolve - instead, that thread will remain suspended forever. You can fix this by callingresregardless of whethercountis2or not - if thecountis less than2, callreswith another invocation ofwaitMore:
res(waitMore());
On the level of the
this.initfunction, in the case that you need to wait more, you need toawait waitMore()(and put the response in a new variable that gets returned) so as to chain the Promise properly:
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
}
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
There are two issues:
Inside
waitMore'ssetTimeout,resis only called ifcount === 2. Otherwise, the created promise never resolves, and whatever might beawaitingwaitMore()will never resolve - instead, that thread will remain suspended forever. You can fix this by callingresregardless of whethercountis2or not - if thecountis less than2, callreswith another invocation ofwaitMore:
res(waitMore());
On the level of the
this.initfunction, in the case that you need to wait more, you need toawait waitMore()(and put the response in a new variable that gets returned) so as to chain the Promise properly:
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
}
function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})function Test() {
this.init = async function() {
var count = 0,
page_job_details = null;
async function waitMore() {
console.log("Wait more loaded - " + (count + 1) + "...");
const p = new Promise((res, rej) => {
setTimeout(() => {
if (count === 2) res({ page_job_details: "khan" });
else {
count++;
res(waitMore());
}
}, 2000);
});
const res = await p;
if (res.page_job_details === '' || res.page_job_details === 'undefined' || res.page_job_details === null) {
console.log("waiting more...");
const newRes = await waitMore();
return newRes;
} else {
console.log("Response is : " + res.page_job_details);
return res;
}
}
var khan;
await waitMore().then(function(r) {
console.log(r);
khan = r;
});
console.log('about to return from init')
return khan;
}
}
new Test().init().then(function(res) {
console.log('in init callback')
console.log(res);
})answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
answered Nov 23 '18 at 6:29
CertainPerformanceCertainPerformance
85.7k154371
85.7k154371
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
add a comment |
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
Perfect, Thank you for your answer !
– Nadeem Ahmad
Nov 23 '18 at 6:34
add a comment |
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Thanks, can you explain what sort of output you were expecting instead?
– CertainPerformance
Nov 23 '18 at 6:17
@CertainPerformance I am expecting the answer in the
res, when theTest().init()is called.– Nadeem Ahmad
Nov 23 '18 at 6:18
You're receiving "khan" at the end of the promise, is not what you want?
– Miguel Angel
Nov 23 '18 at 6:20
@MiguelAngel It's not being chained to the end
.init().thensection– CertainPerformance
Nov 23 '18 at 6:22
I want the results returned by the
init()@MiguelAngel– Nadeem Ahmad
Nov 23 '18 at 6:22