Convert a stream to PromiseFile stream functionsCaching/memoizing promise resultsMongoose promise & error...
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Convert a stream to Promise
File stream functionsCaching/memoizing promise resultsMongoose promise & error handlingExiting a Promise earlyFile existence promiseNode.js stream of objects from MongoDBMemory streambuf and streamNode.js Sequelize PromiseCode refactor with promiseStream wrapper in node.ts
$begingroup$
I need to collect all the data from the stream and resolve it as promise.
I created this stream:
class CollectToPromise extends Writable {
constructor(options) {
super();
this._result = ""
this.result = new Promise((resolve, reject) => {
this.on('finish', resolve):w
this.on('error', reject)
}).then(() => this._result)
}
_write(chunk, encoding, callback) {
this._result += chunk
callback()
}
_writev(chunks, callback) {
chunks.forEach(c => {
this._result += chunk
})
callback()
}
asPromise() {
return this.result
}
}
and I use it like this:
var r = fs.createReadStream('secrets');
const c = new CollectToPromise()
const encrypt = crypto.createCipher(algorithm, password);
r.pipe(encrypt).pipe(c).asPromise().then((res) => console.log(res)
My questions are:
- What do you think about the solution, including the naming?
- How can I avoid the warning:
(node:32386) Warning: Use Cipheriv for counter mode of aes-256-ctr?
javascript node.js stream
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
$endgroup$
bumped to the homepage by Community♦ 2 days ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
add a comment |
$begingroup$
I need to collect all the data from the stream and resolve it as promise.
I created this stream:
class CollectToPromise extends Writable {
constructor(options) {
super();
this._result = ""
this.result = new Promise((resolve, reject) => {
this.on('finish', resolve):w
this.on('error', reject)
}).then(() => this._result)
}
_write(chunk, encoding, callback) {
this._result += chunk
callback()
}
_writev(chunks, callback) {
chunks.forEach(c => {
this._result += chunk
})
callback()
}
asPromise() {
return this.result
}
}
and I use it like this:
var r = fs.createReadStream('secrets');
const c = new CollectToPromise()
const encrypt = crypto.createCipher(algorithm, password);
r.pipe(encrypt).pipe(c).asPromise().then((res) => console.log(res)
My questions are:
- What do you think about the solution, including the naming?
- How can I avoid the warning:
(node:32386) Warning: Use Cipheriv for counter mode of aes-256-ctr?
javascript node.js stream
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
$endgroup$
bumped to the homepage by Community♦ 2 days ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
$begingroup$
asPromisecan be problematic depending on how you implement it. If you create the promise beforeasPromiseis called, and if you reject that Promise due to an error occuring in th stream, then you can get a unhandled promise rejection warning if your code does not use.asPromiseat all, and that waring will result in a real error in future that will exit the application.
$endgroup$
– t.niese
Dec 6 '18 at 12:23
$begingroup$
>then you can get a unhandled promise rejection warning if your code does not use it's probably a downside of using any promise
$endgroup$
– kharandziuk
Dec 6 '18 at 12:43
1
$begingroup$
Tha namingasPromiseimplies that this Promise is created on demand whenasPromiseis called. And not that it already exist before that call. So writing onlyr.pipe(encrypt).pipe(c);should at least not result in a unhandled promise rejection warning. Just because it would break the expectation.
$endgroup$
– t.niese
Dec 6 '18 at 12:50
$begingroup$
Ok, now I see your point, thx
$endgroup$
– kharandziuk
Dec 6 '18 at 12:53
$begingroup$
Missing closing parenthesis)at.then(). Why is second parameter to.then()or.catch()not used to handle error? Does the code at the question return the expected result?
$endgroup$
– guest271314
Jan 29 at 8:41
add a comment |
$begingroup$
I need to collect all the data from the stream and resolve it as promise.
I created this stream:
class CollectToPromise extends Writable {
constructor(options) {
super();
this._result = ""
this.result = new Promise((resolve, reject) => {
this.on('finish', resolve):w
this.on('error', reject)
}).then(() => this._result)
}
_write(chunk, encoding, callback) {
this._result += chunk
callback()
}
_writev(chunks, callback) {
chunks.forEach(c => {
this._result += chunk
})
callback()
}
asPromise() {
return this.result
}
}
and I use it like this:
var r = fs.createReadStream('secrets');
const c = new CollectToPromise()
const encrypt = crypto.createCipher(algorithm, password);
r.pipe(encrypt).pipe(c).asPromise().then((res) => console.log(res)
My questions are:
- What do you think about the solution, including the naming?
- How can I avoid the warning:
(node:32386) Warning: Use Cipheriv for counter mode of aes-256-ctr?
javascript node.js stream
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
$endgroup$
I need to collect all the data from the stream and resolve it as promise.
I created this stream:
class CollectToPromise extends Writable {
constructor(options) {
super();
this._result = ""
this.result = new Promise((resolve, reject) => {
this.on('finish', resolve):w
this.on('error', reject)
}).then(() => this._result)
}
_write(chunk, encoding, callback) {
this._result += chunk
callback()
}
_writev(chunks, callback) {
chunks.forEach(c => {
this._result += chunk
})
callback()
}
asPromise() {
return this.result
}
}
and I use it like this:
var r = fs.createReadStream('secrets');
const c = new CollectToPromise()
const encrypt = crypto.createCipher(algorithm, password);
r.pipe(encrypt).pipe(c).asPromise().then((res) => console.log(res)
My questions are:
- What do you think about the solution, including the naming?
- How can I avoid the warning:
(node:32386) Warning: Use Cipheriv for counter mode of aes-256-ctr?
javascript node.js stream
javascript node.js stream
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
edited Dec 23 '18 at 0:43
Jamal♦
30.3k11119227
30.3k11119227
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
asked Dec 6 '18 at 11:15
kharandziukkharandziuk
4371316
4371316
bumped to the homepage by Community♦ 2 days ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
bumped to the homepage by Community♦ 2 days ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
$begingroup$
asPromisecan be problematic depending on how you implement it. If you create the promise beforeasPromiseis called, and if you reject that Promise due to an error occuring in th stream, then you can get a unhandled promise rejection warning if your code does not use.asPromiseat all, and that waring will result in a real error in future that will exit the application.
$endgroup$
– t.niese
Dec 6 '18 at 12:23
$begingroup$
>then you can get a unhandled promise rejection warning if your code does not use it's probably a downside of using any promise
$endgroup$
– kharandziuk
Dec 6 '18 at 12:43
1
$begingroup$
Tha namingasPromiseimplies that this Promise is created on demand whenasPromiseis called. And not that it already exist before that call. So writing onlyr.pipe(encrypt).pipe(c);should at least not result in a unhandled promise rejection warning. Just because it would break the expectation.
$endgroup$
– t.niese
Dec 6 '18 at 12:50
$begingroup$
Ok, now I see your point, thx
$endgroup$
– kharandziuk
Dec 6 '18 at 12:53
$begingroup$
Missing closing parenthesis)at.then(). Why is second parameter to.then()or.catch()not used to handle error? Does the code at the question return the expected result?
$endgroup$
– guest271314
Jan 29 at 8:41
add a comment |
$begingroup$
asPromisecan be problematic depending on how you implement it. If you create the promise beforeasPromiseis called, and if you reject that Promise due to an error occuring in th stream, then you can get a unhandled promise rejection warning if your code does not use.asPromiseat all, and that waring will result in a real error in future that will exit the application.
$endgroup$
– t.niese
Dec 6 '18 at 12:23
$begingroup$
>then you can get a unhandled promise rejection warning if your code does not use it's probably a downside of using any promise
$endgroup$
– kharandziuk
Dec 6 '18 at 12:43
1
$begingroup$
Tha namingasPromiseimplies that this Promise is created on demand whenasPromiseis called. And not that it already exist before that call. So writing onlyr.pipe(encrypt).pipe(c);should at least not result in a unhandled promise rejection warning. Just because it would break the expectation.
$endgroup$
– t.niese
Dec 6 '18 at 12:50
$begingroup$
Ok, now I see your point, thx
$endgroup$
– kharandziuk
Dec 6 '18 at 12:53
$begingroup$
Missing closing parenthesis)at.then(). Why is second parameter to.then()or.catch()not used to handle error? Does the code at the question return the expected result?
$endgroup$
– guest271314
Jan 29 at 8:41
$begingroup$
asPromise can be problematic depending on how you implement it. If you create the promise before asPromise is called, and if you reject that Promise due to an error occuring in th stream, then you can get a unhandled promise rejection warning if your code does not use .asPromise at all, and that waring will result in a real error in future that will exit the application.$endgroup$
– t.niese
Dec 6 '18 at 12:23
$begingroup$
asPromise can be problematic depending on how you implement it. If you create the promise before asPromise is called, and if you reject that Promise due to an error occuring in th stream, then you can get a unhandled promise rejection warning if your code does not use .asPromise at all, and that waring will result in a real error in future that will exit the application.$endgroup$
– t.niese
Dec 6 '18 at 12:23
$begingroup$
>then you can get a unhandled promise rejection warning if your code does not use it's probably a downside of using any promise
$endgroup$
– kharandziuk
Dec 6 '18 at 12:43
$begingroup$
>then you can get a unhandled promise rejection warning if your code does not use it's probably a downside of using any promise
$endgroup$
– kharandziuk
Dec 6 '18 at 12:43
1
1
$begingroup$
Tha naming
asPromise implies that this Promise is created on demand when asPromise is called. And not that it already exist before that call. So writing only r.pipe(encrypt).pipe(c); should at least not result in a unhandled promise rejection warning. Just because it would break the expectation.$endgroup$
– t.niese
Dec 6 '18 at 12:50
$begingroup$
Tha naming
asPromise implies that this Promise is created on demand when asPromise is called. And not that it already exist before that call. So writing only r.pipe(encrypt).pipe(c); should at least not result in a unhandled promise rejection warning. Just because it would break the expectation.$endgroup$
– t.niese
Dec 6 '18 at 12:50
$begingroup$
Ok, now I see your point, thx
$endgroup$
– kharandziuk
Dec 6 '18 at 12:53
$begingroup$
Ok, now I see your point, thx
$endgroup$
– kharandziuk
Dec 6 '18 at 12:53
$begingroup$
Missing closing parenthesis
) at .then(). Why is second parameter to .then() or .catch() not used to handle error? Does the code at the question return the expected result?$endgroup$
– guest271314
Jan 29 at 8:41
$begingroup$
Missing closing parenthesis
) at .then(). Why is second parameter to .then() or .catch() not used to handle error? Does the code at the question return the expected result?$endgroup$
– guest271314
Jan 29 at 8:41
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
I am not sure I understand why you are attempting to extend Writable here.
At the end of the day, it seems as if your pipeline is what you are REALLY wanting to have a promise interface.
Luckily this is really easy to do with recent versions of node using Stream.pipeline and Util.promisify(). There is an even an example in the Stream.pipeline documentation
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
$endgroup$
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
add a comment |
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1 Answer
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$begingroup$
I am not sure I understand why you are attempting to extend Writable here.
At the end of the day, it seems as if your pipeline is what you are REALLY wanting to have a promise interface.
Luckily this is really easy to do with recent versions of node using Stream.pipeline and Util.promisify(). There is an even an example in the Stream.pipeline documentation
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
$endgroup$
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
add a comment |
$begingroup$
I am not sure I understand why you are attempting to extend Writable here.
At the end of the day, it seems as if your pipeline is what you are REALLY wanting to have a promise interface.
Luckily this is really easy to do with recent versions of node using Stream.pipeline and Util.promisify(). There is an even an example in the Stream.pipeline documentation
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
$endgroup$
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
add a comment |
$begingroup$
I am not sure I understand why you are attempting to extend Writable here.
At the end of the day, it seems as if your pipeline is what you are REALLY wanting to have a promise interface.
Luckily this is really easy to do with recent versions of node using Stream.pipeline and Util.promisify(). There is an even an example in the Stream.pipeline documentation
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
$endgroup$
I am not sure I understand why you are attempting to extend Writable here.
At the end of the day, it seems as if your pipeline is what you are REALLY wanting to have a promise interface.
Luckily this is really easy to do with recent versions of node using Stream.pipeline and Util.promisify(). There is an even an example in the Stream.pipeline documentation
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
answered Jan 28 at 15:54
Mike BrantMike Brant
8,823622
8,823622
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
add a comment |
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
$begingroup$
Why do I need it? for example testing - it's quite handy to have a result is promise for testing. Stream.pipeline - I don't have a 'collected' result with it
$endgroup$
– kharandziuk
Jan 28 at 16:59
add a comment |
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$begingroup$
asPromisecan be problematic depending on how you implement it. If you create the promise beforeasPromiseis called, and if you reject that Promise due to an error occuring in th stream, then you can get a unhandled promise rejection warning if your code does not use.asPromiseat all, and that waring will result in a real error in future that will exit the application.$endgroup$
– t.niese
Dec 6 '18 at 12:23
$begingroup$
>then you can get a unhandled promise rejection warning if your code does not use it's probably a downside of using any promise
$endgroup$
– kharandziuk
Dec 6 '18 at 12:43
1
$begingroup$
Tha naming
asPromiseimplies that this Promise is created on demand whenasPromiseis called. And not that it already exist before that call. So writing onlyr.pipe(encrypt).pipe(c);should at least not result in a unhandled promise rejection warning. Just because it would break the expectation.$endgroup$
– t.niese
Dec 6 '18 at 12:50
$begingroup$
Ok, now I see your point, thx
$endgroup$
– kharandziuk
Dec 6 '18 at 12:53
$begingroup$
Missing closing parenthesis
)at.then(). Why is second parameter to.then()or.catch()not used to handle error? Does the code at the question return the expected result?$endgroup$
– guest271314
Jan 29 at 8:41