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?

asked Nov 15 '18 at 23:33

Jae

91131123

Possible duplicate of async/await implicitly returns promise?

– lucascaro
Nov 15 '18 at 23:35

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

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?

asked Nov 15 '18 at 23:33

Jae

91131123

Possible duplicate of async/await implicitly returns promise?

– lucascaro
Nov 15 '18 at 23:35

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

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?

asked Nov 15 '18 at 23:33

Jae

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

asked Nov 15 '18 at 23:33

Jae

91131123

asked Nov 15 '18 at 23:33

Jae

91131123

asked Nov 15 '18 at 23:33

Jae

91131123

asked Nov 15 '18 at 23:33

Jae

91131123

asked Nov 15 '18 at 23:33

Jae

91131123

Possible duplicate of async/await implicitly returns promise?

– lucascaro
Nov 15 '18 at 23:35

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

add a comment |

Possible duplicate of async/await implicitly returns promise?

– lucascaro
Nov 15 '18 at 23:35

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

Possible duplicate of async/await implicitly returns promise?

– lucascaro
Nov 15 '18 at 23:35

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

jfriend00

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

Paulpro

114k15226232

add a comment |

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2 Answers
2

active

oldest

votes

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

jfriend00

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

jfriend00

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

jfriend00

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

jfriend00

438k55575619

answered Nov 15 '18 at 23:35

jfriend00

438k55575619

answered Nov 15 '18 at 23:35

jfriend00

438k55575619

answered Nov 15 '18 at 23:35

jfriend00

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

Paulpro

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

Paulpro

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

Paulpro

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

Paulpro

114k15226232

answered Nov 16 '18 at 0:12

Paulpro

114k15226232

answered Nov 16 '18 at 0:12

Paulpro

114k15226232

answered Nov 16 '18 at 0:12

Paulpro

114k15226232

add a comment |

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