how to call async function in .on event nodejs
-1
I am reading a CSV file using csv-parser npm module createReadStream.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', data =>
const val = await fun(param1, param2, param3);
);
fun(param1, param2, param3)
return true;
I have to call function fun with await but it is throwing me the error.await is only valid in async function. Can anyone help me how to fix this?
javascript node.js events
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
add a comment |
-1
I am reading a CSV file using csv-parser npm module createReadStream.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', data =>
const val = await fun(param1, param2, param3);
);
fun(param1, param2, param3)
return true;
I have to call function fun with await but it is throwing me the error.await is only valid in async function. Can anyone help me how to fix this?
javascript node.js events
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
add a comment |
-1
-1
-1
I am reading a CSV file using csv-parser npm module createReadStream.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', data =>
const val = await fun(param1, param2, param3);
);
fun(param1, param2, param3)
return true;
I have to call function fun with await but it is throwing me the error.await is only valid in async function. Can anyone help me how to fix this?
javascript node.js events
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
I am reading a CSV file using csv-parser npm module createReadStream.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', data =>
const val = await fun(param1, param2, param3);
);
fun(param1, param2, param3)
return true;
I have to call function fun with await but it is throwing me the error.await is only valid in async function. Can anyone help me how to fix this?
javascript node.js events
javascript node.js events
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
asked Nov 13 '18 at 13:05
m9m9mm9m9m
497512
497512
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
2
Just indicate that the callback function is async.
stream.on('data', async data =>
// Do async stuff
)
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
add a comment |
0
The function that you await must return a promise.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', async data =>
try
const val = await fun(param1, param2, param3);
catch(err)
//handle error
);
fun(param1, param2, param3)
return new Promise((resolve, reject)=>
resolve(some_value)
)
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
1
It needs to be specified asasyncand that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited
– Aluan Haddad
Nov 13 '18 at 13:27
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
2
Just indicate that the callback function is async.
stream.on('data', async data =>
// Do async stuff
)
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
add a comment |
2
Just indicate that the callback function is async.
stream.on('data', async data =>
// Do async stuff
)
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
add a comment |
2
2
2
Just indicate that the callback function is async.
stream.on('data', async data =>
// Do async stuff
)
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
Just indicate that the callback function is async.
stream.on('data', async data =>
// Do async stuff
)
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
answered Nov 13 '18 at 13:07
EnslevEnslev
40527
40527
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
add a comment |
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
each data has a JSON object and I have written a function call in call back function. Which is calling by all the objects at once. Can you tell me why? and I want to call the function in callback function one after once.
– m9m9m
Nov 14 '18 at 4:58
add a comment |
0
The function that you await must return a promise.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', async data =>
try
const val = await fun(param1, param2, param3);
catch(err)
//handle error
);
fun(param1, param2, param3)
return new Promise((resolve, reject)=>
resolve(some_value)
)
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
1
It needs to be specified asasyncand that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited
– Aluan Haddad
Nov 13 '18 at 13:27
add a comment |
0
The function that you await must return a promise.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', async data =>
try
const val = await fun(param1, param2, param3);
catch(err)
//handle error
);
fun(param1, param2, param3)
return new Promise((resolve, reject)=>
resolve(some_value)
)
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
1
It needs to be specified asasyncand that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited
– Aluan Haddad
Nov 13 '18 at 13:27
add a comment |
0
0
0
The function that you await must return a promise.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', async data =>
try
const val = await fun(param1, param2, param3);
catch(err)
//handle error
);
fun(param1, param2, param3)
return new Promise((resolve, reject)=>
resolve(some_value)
)
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
The function that you await must return a promise.
export default async function main()
const readstream = fs.createReadStream('src/working_file.csv');
stream.on('data', async data =>
try
const val = await fun(param1, param2, param3);
catch(err)
//handle error
);
fun(param1, param2, param3)
return new Promise((resolve, reject)=>
resolve(some_value)
)
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
edited Nov 13 '18 at 13:24
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
answered Nov 13 '18 at 13:19
squeekyDavesqueekyDave
417215
417215
1
It needs to be specified asasyncand that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited
– Aluan Haddad
Nov 13 '18 at 13:27
add a comment |
1
It needs to be specified asasyncand that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited
– Aluan Haddad
Nov 13 '18 at 13:27
1
1
It needs to be specified as
async and that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited– Aluan Haddad
Nov 13 '18 at 13:27
It needs to be specified as
async and that very change means it does return a promise, by definition. An expression that is awaited is wrapped in a promise meaning that anything may be awaited– Aluan Haddad
Nov 13 '18 at 13:27
add a comment |
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