Using async function within synchronous code
I'm using a library called sqs-consumer to process SQS messages. The library is expecting the message handler to look like:
handleMessage: (message, done) =>
// do some work with `message`
done();
On the other hand though I have async code
async function sendEmail()
return await ...
Is there a good way to run the sendEmail within handleMessage, wait for it to finish, and then to call done?
node.js
asked Nov 15 '18 at 23:33
JaeJae
91131123
add a comment |
I'm using a library called sqs-consumer to process SQS messages. The library is expecting the message handler to look like:
handleMessage: (message, done) =>
// do some work with `message`
done();
On the other hand though I have async code
async function sendEmail()
return await ...
Is there a good way to run the sendEmail within handleMessage, wait for it to finish, and then to call done?
node.js
asked Nov 15 '18 at 23:33
JaeJae
91131123
Possible duplicate of async/await implicitly returns promise?
– lucascaro
Nov 15 '18 at 23:35
2
Note thatreturn awaitis pretty pointless if that's the onlyawaityou're using in the function - just use a standard function instead, and you can simplyreturnthe plainPromise
– CertainPerformance
Nov 15 '18 at 23:36
add a comment |
I'm using a library called sqs-consumer to process SQS messages. The library is expecting the message handler to look like:
handleMessage: (message, done) =>
// do some work with `message`
done();
On the other hand though I have async code
async function sendEmail()
return await ...
Is there a good way to run the sendEmail within handleMessage, wait for it to finish, and then to call done?
node.js
asked Nov 15 '18 at 23:33
JaeJae
91131123
I'm using a library called sqs-consumer to process SQS messages. The library is expecting the message handler to look like:
handleMessage: (message, done) =>
// do some work with `message`
done();
On the other hand though I have async code
async function sendEmail()
return await ...
Is there a good way to run the sendEmail within handleMessage, wait for it to finish, and then to call done?
node.js
node.js
asked Nov 15 '18 at 23:33
JaeJae
91131123
asked Nov 15 '18 at 23:33
JaeJae
91131123
asked Nov 15 '18 at 23:33
JaeJae
91131123
asked Nov 15 '18 at 23:33
JaeJae
91131123
asked Nov 15 '18 at 23:33
JaeJae
91131123
91131123
Possible duplicate of async/await implicitly returns promise?
– lucascaro
Nov 15 '18 at 23:35
2
Note thatreturn awaitis pretty pointless if that's the onlyawaityou're using in the function - just use a standard function instead, and you can simplyreturnthe plainPromise
– CertainPerformance
Nov 15 '18 at 23:36
add a comment |
Possible duplicate of async/await implicitly returns promise?
– lucascaro
Nov 15 '18 at 23:35
2
Note thatreturn awaitis pretty pointless if that's the onlyawaityou're using in the function - just use a standard function instead, and you can simplyreturnthe plainPromise
– CertainPerformance
Nov 15 '18 at 23:36
Possible duplicate of async/await implicitly returns promise?
– lucascaro
Nov 15 '18 at 23:35
Possible duplicate of async/await implicitly returns promise?
– lucascaro
Nov 15 '18 at 23:35
2
2
Note that
return await is pretty pointless if that's the only await you're using in the function - just use a standard function instead, and you can simply return the plain Promise– CertainPerformance
Nov 15 '18 at 23:36
Note that
return await is pretty pointless if that's the only await you're using in the function - just use a standard function instead, and you can simply return the plain Promise– CertainPerformance
Nov 15 '18 at 23:36
add a comment |
2 Answers
2
active
oldest
votes
You can use your promise-based code inside a callback like this:
handleMessage: (message, done) =>
// do some work with `message`
sendEmail().then(done).catch(...);
In some cases, you could also make a new method for handleMessage() that actually expects a promise to be returned and works with that promise directly rather than using a plain callback at all.
Also, not that there is no point to using return await ... at the end of your function. You can just return the promise directly:
So, instead of:
async function sendEmail()
// other code here
return await someFuncThatReturnsPromise();
You can just do:
async function sendEmail()
// other code here
return someFuncThatReturnsPromise();
That extra await adds no value or utility.
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
add a comment |
As long as the library doesn't care what you return from handleMessage you can also use async/await in the handlerMessage function directly:
handleMessage: async (message, done) =>
await sendEmail();
done();
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
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
You can use your promise-based code inside a callback like this:
handleMessage: (message, done) =>
// do some work with `message`
sendEmail().then(done).catch(...);
In some cases, you could also make a new method for handleMessage() that actually expects a promise to be returned and works with that promise directly rather than using a plain callback at all.
Also, not that there is no point to using return await ... at the end of your function. You can just return the promise directly:
So, instead of:
async function sendEmail()
// other code here
return await someFuncThatReturnsPromise();
You can just do:
async function sendEmail()
// other code here
return someFuncThatReturnsPromise();
That extra await adds no value or utility.
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
add a comment |
You can use your promise-based code inside a callback like this:
handleMessage: (message, done) =>
// do some work with `message`
sendEmail().then(done).catch(...);
In some cases, you could also make a new method for handleMessage() that actually expects a promise to be returned and works with that promise directly rather than using a plain callback at all.
Also, not that there is no point to using return await ... at the end of your function. You can just return the promise directly:
So, instead of:
async function sendEmail()
// other code here
return await someFuncThatReturnsPromise();
You can just do:
async function sendEmail()
// other code here
return someFuncThatReturnsPromise();
That extra await adds no value or utility.
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
add a comment |
You can use your promise-based code inside a callback like this:
handleMessage: (message, done) =>
// do some work with `message`
sendEmail().then(done).catch(...);
In some cases, you could also make a new method for handleMessage() that actually expects a promise to be returned and works with that promise directly rather than using a plain callback at all.
Also, not that there is no point to using return await ... at the end of your function. You can just return the promise directly:
So, instead of:
async function sendEmail()
// other code here
return await someFuncThatReturnsPromise();
You can just do:
async function sendEmail()
// other code here
return someFuncThatReturnsPromise();
That extra await adds no value or utility.
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
You can use your promise-based code inside a callback like this:
handleMessage: (message, done) =>
// do some work with `message`
sendEmail().then(done).catch(...);
In some cases, you could also make a new method for handleMessage() that actually expects a promise to be returned and works with that promise directly rather than using a plain callback at all.
Also, not that there is no point to using return await ... at the end of your function. You can just return the promise directly:
So, instead of:
async function sendEmail()
// other code here
return await someFuncThatReturnsPromise();
You can just do:
async function sendEmail()
// other code here
return someFuncThatReturnsPromise();
That extra await adds no value or utility.
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
answered Nov 15 '18 at 23:35
jfriend00jfriend00
438k55575619
438k55575619
add a comment |
add a comment |
As long as the library doesn't care what you return from handleMessage you can also use async/await in the handlerMessage function directly:
handleMessage: async (message, done) =>
await sendEmail();
done();
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
add a comment |
As long as the library doesn't care what you return from handleMessage you can also use async/await in the handlerMessage function directly:
handleMessage: async (message, done) =>
await sendEmail();
done();
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
add a comment |
As long as the library doesn't care what you return from handleMessage you can also use async/await in the handlerMessage function directly:
handleMessage: async (message, done) =>
await sendEmail();
done();
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
As long as the library doesn't care what you return from handleMessage you can also use async/await in the handlerMessage function directly:
handleMessage: async (message, done) =>
await sendEmail();
done();
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
answered Nov 16 '18 at 0:12
PaulproPaulpro
114k15226232
114k15226232
add a comment |
add a comment |
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Possible duplicate of async/await implicitly returns promise?
– lucascaro
Nov 15 '18 at 23:35
2
Note that
return awaitis pretty pointless if that's the onlyawaityou're using in the function - just use a standard function instead, and you can simplyreturnthe plainPromise– CertainPerformance
Nov 15 '18 at 23:36