What is the purpose of thunkToPromise in the co coroutine lib?
I know co is kind of outdated but I am still interested in how it works. I find it hard to understand the purpose of the thunkToPromise function, though:
function thunkToPromise(fn) {
var ctx = this;
return new Promise(function (res, rej) {
fn.call(ctx, function (err, res) {
if (err) return rej(err);
if (arguments.length > 2) res = slice.call(arguments, 1);
res(res);
});
});
}
A thunk is a function without parameters, but fn is still called with one argument. In addition there is this weird recursive call res(res), which usually results in a stack overflow. What's going on here? How would I apply thunkToPromise so that it does something meaningful?
javascript promise coroutine thunk
add a comment |
I know co is kind of outdated but I am still interested in how it works. I find it hard to understand the purpose of the thunkToPromise function, though:
function thunkToPromise(fn) {
var ctx = this;
return new Promise(function (res, rej) {
fn.call(ctx, function (err, res) {
if (err) return rej(err);
if (arguments.length > 2) res = slice.call(arguments, 1);
res(res);
});
});
}
A thunk is a function without parameters, but fn is still called with one argument. In addition there is this weird recursive call res(res), which usually results in a stack overflow. What's going on here? How would I apply thunkToPromise so that it does something meaningful?
javascript promise coroutine thunk
add a comment |
I know co is kind of outdated but I am still interested in how it works. I find it hard to understand the purpose of the thunkToPromise function, though:
function thunkToPromise(fn) {
var ctx = this;
return new Promise(function (res, rej) {
fn.call(ctx, function (err, res) {
if (err) return rej(err);
if (arguments.length > 2) res = slice.call(arguments, 1);
res(res);
});
});
}
A thunk is a function without parameters, but fn is still called with one argument. In addition there is this weird recursive call res(res), which usually results in a stack overflow. What's going on here? How would I apply thunkToPromise so that it does something meaningful?
javascript promise coroutine thunk
I know co is kind of outdated but I am still interested in how it works. I find it hard to understand the purpose of the thunkToPromise function, though:
function thunkToPromise(fn) {
var ctx = this;
return new Promise(function (res, rej) {
fn.call(ctx, function (err, res) {
if (err) return rej(err);
if (arguments.length > 2) res = slice.call(arguments, 1);
res(res);
});
});
}
A thunk is a function without parameters, but fn is still called with one argument. In addition there is this weird recursive call res(res), which usually results in a stack overflow. What's going on here? How would I apply thunkToPromise so that it does something meaningful?
javascript promise coroutine thunk
javascript promise coroutine thunk
asked Nov 24 '18 at 10:13
user10675354
add a comment |
add a comment |
1 Answer
1
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A thunk is a function without parameters
No. A thunk is a function that takes only a callback to forward its result. It does take no data parameters, that's true, only an "output parameter".
In addition there is this weird recursive call
res(res)
It's not recursive, it's just broken. Someone mixed up result and resolve. Did you find this in a current release of the library?
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
res(res)was indeed my fault, when I thoughtless usedfind/replace allin sublime. Sorry for that!
– user10675354
Nov 24 '18 at 12:58
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
A thunk is a function without parameters
No. A thunk is a function that takes only a callback to forward its result. It does take no data parameters, that's true, only an "output parameter".
In addition there is this weird recursive call
res(res)
It's not recursive, it's just broken. Someone mixed up result and resolve. Did you find this in a current release of the library?
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
res(res)was indeed my fault, when I thoughtless usedfind/replace allin sublime. Sorry for that!
– user10675354
Nov 24 '18 at 12:58
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
add a comment |
A thunk is a function without parameters
No. A thunk is a function that takes only a callback to forward its result. It does take no data parameters, that's true, only an "output parameter".
In addition there is this weird recursive call
res(res)
It's not recursive, it's just broken. Someone mixed up result and resolve. Did you find this in a current release of the library?
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
res(res)was indeed my fault, when I thoughtless usedfind/replace allin sublime. Sorry for that!
– user10675354
Nov 24 '18 at 12:58
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
add a comment |
A thunk is a function without parameters
No. A thunk is a function that takes only a callback to forward its result. It does take no data parameters, that's true, only an "output parameter".
In addition there is this weird recursive call
res(res)
It's not recursive, it's just broken. Someone mixed up result and resolve. Did you find this in a current release of the library?
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
A thunk is a function without parameters
No. A thunk is a function that takes only a callback to forward its result. It does take no data parameters, that's true, only an "output parameter".
In addition there is this weird recursive call
res(res)
It's not recursive, it's just broken. Someone mixed up result and resolve. Did you find this in a current release of the library?
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
answered Nov 24 '18 at 12:17
BergiBergi
373k59562892
373k59562892
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
res(res)was indeed my fault, when I thoughtless usedfind/replace allin sublime. Sorry for that!
– user10675354
Nov 24 '18 at 12:58
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
add a comment |
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
res(res)was indeed my fault, when I thoughtless usedfind/replace allin sublime. Sorry for that!
– user10675354
Nov 24 '18 at 12:58
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
Do you mean a thunk in the context of coroutines always expects a continuation? That would make sense.
– user10675354
Nov 24 '18 at 12:56
res(res) was indeed my fault, when I thoughtless used find/replace all in sublime. Sorry for that!– user10675354
Nov 24 '18 at 12:58
res(res) was indeed my fault, when I thoughtless used find/replace all in sublime. Sorry for that!– user10675354
Nov 24 '18 at 12:58
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
@reify Yes, a thunk is a value that needs a continuation.
– Bergi
Nov 24 '18 at 14:27
add a comment |
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