RxJS 6 / When does tap operator emit a value
I've been wondering if it's safe to assume that after the using the tap operator, the side effect inside it has completed.
My use case is with ngrx.
...
tap(() =>
this.store.dispatch(new SetValue("Hello World"));
}),
switchMap(() => this.store),
select(state => state.value),
tap(state =>
if (state === undefined)
throw new Error("Couldn't find value");
)
SetValue is an class that implements ngrx
export class SetValue implements Action
readonly type = SET_VALUE;
constructor(public payload: string)
What I'm trying to implement is to set a value on the store and then check if it's effectively been set.
Can I assume the dispatch has completed after tap operator?
rxjs ngrx rxjs5 rxjs6 ngrx-store
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
add a comment |
I've been wondering if it's safe to assume that after the using the tap operator, the side effect inside it has completed.
My use case is with ngrx.
...
tap(() =>
this.store.dispatch(new SetValue("Hello World"));
}),
switchMap(() => this.store),
select(state => state.value),
tap(state =>
if (state === undefined)
throw new Error("Couldn't find value");
)
SetValue is an class that implements ngrx
export class SetValue implements Action
readonly type = SET_VALUE;
constructor(public payload: string)
What I'm trying to implement is to set a value on the store and then check if it's effectively been set.
Can I assume the dispatch has completed after tap operator?
rxjs ngrx rxjs5 rxjs6 ngrx-store
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
I was thinking about my code too imperativly, my suggestion to any one encoutering this, is to encourage reactive programming, thinking about steams and when it sends data
– Guido Dizioli
Nov 16 '18 at 18:14
add a comment |
I've been wondering if it's safe to assume that after the using the tap operator, the side effect inside it has completed.
My use case is with ngrx.
...
tap(() =>
this.store.dispatch(new SetValue("Hello World"));
}),
switchMap(() => this.store),
select(state => state.value),
tap(state =>
if (state === undefined)
throw new Error("Couldn't find value");
)
SetValue is an class that implements ngrx
export class SetValue implements Action
readonly type = SET_VALUE;
constructor(public payload: string)
What I'm trying to implement is to set a value on the store and then check if it's effectively been set.
Can I assume the dispatch has completed after tap operator?
rxjs ngrx rxjs5 rxjs6 ngrx-store
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
I've been wondering if it's safe to assume that after the using the tap operator, the side effect inside it has completed.
My use case is with ngrx.
...
tap(() =>
this.store.dispatch(new SetValue("Hello World"));
}),
switchMap(() => this.store),
select(state => state.value),
tap(state =>
if (state === undefined)
throw new Error("Couldn't find value");
)
SetValue is an class that implements ngrx
export class SetValue implements Action
readonly type = SET_VALUE;
constructor(public payload: string)
What I'm trying to implement is to set a value on the store and then check if it's effectively been set.
Can I assume the dispatch has completed after tap operator?
rxjs ngrx rxjs5 rxjs6 ngrx-store
rxjs ngrx rxjs5 rxjs6 ngrx-store
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
edited Nov 16 '18 at 18:13
Guido Dizioli
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
asked Nov 13 '18 at 14:06
Guido DizioliGuido Dizioli
168111
168111
I was thinking about my code too imperativly, my suggestion to any one encoutering this, is to encourage reactive programming, thinking about steams and when it sends data
– Guido Dizioli
Nov 16 '18 at 18:14
add a comment |
I was thinking about my code too imperativly, my suggestion to any one encoutering this, is to encourage reactive programming, thinking about steams and when it sends data
– Guido Dizioli
Nov 16 '18 at 18:14
I was thinking about my code too imperativly, my suggestion to any one encoutering this, is to encourage reactive programming, thinking about steams and when it sends data
– Guido Dizioli
Nov 16 '18 at 18:14
I was thinking about my code too imperativly, my suggestion to any one encoutering this, is to encourage reactive programming, thinking about steams and when it sends data
– Guido Dizioli
Nov 16 '18 at 18:14
add a comment |
1 Answer
1
active
oldest
votes
Most operations in RxJS are synchronous so if this.store.dispatch(new SetValue("Hello World")) won't do any async task it probably will work as expected (it's still just a Subject under the hood).
However, you shouldn't rely on this behavior. NgRx might change it's internals and in general it's better not to rely on synchronicity/asynchronicity of RxJS operators (this has already happened in the past in eg. from() from RxJS 4 to RxJS 5).
If you want to make sure something has been set then change your new SetValue("Hello World") effect to emit another action after it's done doing what it needs to do.
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
SetValue is a class that implements action from ngrx, how does your suggestion fit in?export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string)
– Guido Dizioli
Nov 13 '18 at 14:35
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handlingSetValueaction you map it to another action telling you thatSetValuehas finished.
– martin
Nov 13 '18 at 14:39
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
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
Most operations in RxJS are synchronous so if this.store.dispatch(new SetValue("Hello World")) won't do any async task it probably will work as expected (it's still just a Subject under the hood).
However, you shouldn't rely on this behavior. NgRx might change it's internals and in general it's better not to rely on synchronicity/asynchronicity of RxJS operators (this has already happened in the past in eg. from() from RxJS 4 to RxJS 5).
If you want to make sure something has been set then change your new SetValue("Hello World") effect to emit another action after it's done doing what it needs to do.
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
SetValue is a class that implements action from ngrx, how does your suggestion fit in?export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string)
– Guido Dizioli
Nov 13 '18 at 14:35
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handlingSetValueaction you map it to another action telling you thatSetValuehas finished.
– martin
Nov 13 '18 at 14:39
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
add a comment |
Most operations in RxJS are synchronous so if this.store.dispatch(new SetValue("Hello World")) won't do any async task it probably will work as expected (it's still just a Subject under the hood).
However, you shouldn't rely on this behavior. NgRx might change it's internals and in general it's better not to rely on synchronicity/asynchronicity of RxJS operators (this has already happened in the past in eg. from() from RxJS 4 to RxJS 5).
If you want to make sure something has been set then change your new SetValue("Hello World") effect to emit another action after it's done doing what it needs to do.
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
SetValue is a class that implements action from ngrx, how does your suggestion fit in?export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string)
– Guido Dizioli
Nov 13 '18 at 14:35
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handlingSetValueaction you map it to another action telling you thatSetValuehas finished.
– martin
Nov 13 '18 at 14:39
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
add a comment |
Most operations in RxJS are synchronous so if this.store.dispatch(new SetValue("Hello World")) won't do any async task it probably will work as expected (it's still just a Subject under the hood).
However, you shouldn't rely on this behavior. NgRx might change it's internals and in general it's better not to rely on synchronicity/asynchronicity of RxJS operators (this has already happened in the past in eg. from() from RxJS 4 to RxJS 5).
If you want to make sure something has been set then change your new SetValue("Hello World") effect to emit another action after it's done doing what it needs to do.
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
Most operations in RxJS are synchronous so if this.store.dispatch(new SetValue("Hello World")) won't do any async task it probably will work as expected (it's still just a Subject under the hood).
However, you shouldn't rely on this behavior. NgRx might change it's internals and in general it's better not to rely on synchronicity/asynchronicity of RxJS operators (this has already happened in the past in eg. from() from RxJS 4 to RxJS 5).
If you want to make sure something has been set then change your new SetValue("Hello World") effect to emit another action after it's done doing what it needs to do.
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
answered Nov 13 '18 at 14:13
martinmartin
42.7k1187128
42.7k1187128
SetValue is a class that implements action from ngrx, how does your suggestion fit in?export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string)
– Guido Dizioli
Nov 13 '18 at 14:35
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handlingSetValueaction you map it to another action telling you thatSetValuehas finished.
– martin
Nov 13 '18 at 14:39
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
add a comment |
SetValue is a class that implements action from ngrx, how does your suggestion fit in?export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string)
– Guido Dizioli
Nov 13 '18 at 14:35
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handlingSetValueaction you map it to another action telling you thatSetValuehas finished.
– martin
Nov 13 '18 at 14:39
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
SetValue is a class that implements action from ngrx, how does your suggestion fit in?
export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string) – Guido Dizioli
Nov 13 '18 at 14:35
SetValue is a class that implements action from ngrx, how does your suggestion fit in?
export class SetValue implements Action readonly type = SET_VALUE; constructor(public payload: string) – Guido Dizioli
Nov 13 '18 at 14:35
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handling
SetValue action you map it to another action telling you that SetValue has finished.– martin
Nov 13 '18 at 14:39
You probably handle this action in another effect because I guess you don't create an action that does nothing. So when it's done handling
SetValue action you map it to another action telling you that SetValue has finished.– martin
Nov 13 '18 at 14:39
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
I'm editing the question to a the real world problem. I'm trying to provide values on store with a RouteGuard based on the url. That is where the action dispatch. I'd like to check that values have been succesfully filled in the store, otherwise redirect to another page
– Guido Dizioli
Nov 13 '18 at 14:43
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
Adding to what @martin said, the ngrx also recommends us to same. Have Success/Fail action emitted based on the Load/Set Action. Then you can listen to loaded/error states updated by Success/Fail action and decide on navigating away.
– KiraAG
Nov 14 '18 at 5:47
add a comment |
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I was thinking about my code too imperativly, my suggestion to any one encoutering this, is to encourage reactive programming, thinking about steams and when it sends data
– Guido Dizioli
Nov 16 '18 at 18:14