Ngrx dispatch one action multiple times at once
angular, ngrx, ngrx-effects, ngrx-store, redux
Solution
As @cartant mentioned in a comment, replace `switchMap` with `mergeMap`.
The difference being, `switchMap` will switch contexts everytime the parent observable fires and `mergeMap` will keep listening to the parent observable and merge or combine the results.
SwitchMap
In essence the `switchMap` is unsubscribing from the parent observable's first stream when the parent observable emits a new value.
In the marble diagram, you can see when `3` is emitted and then `5` is emitted, the final output doesn't include 3 `30`s because when `5` was emitted, it switched contexts and the values are dropped.
MergeMap
MergeMap will merge all the values emitted from the parent observable.
In the marble diagram for `mergeMap` you can see all values get emitted for every value emitted from the parent observable. ie, all `30`s get emitted, even though the last value comes in after `5` is emitted from the parent.
Hope that helps illustrate it a little better.
Problem
My app has 3 download buttons Each button click will dispatch DownloadFileAction(payload=fileId) An Effect will keep listening for Download_File_Action type ``` @effect() download_attachment$: Observable = this.actions$ .ofType(FileActions.ActionTypes.DOWNLOAD_ATTACHMENT) .map(toPayload) .switchMap( attachment => { return this.service.downloadAttachment(attachment.link) //absolute link .map( (data) => { this.service.saveAttachment(data); //save file locally return new FileActions.DownloadAttachmentSuccessAction(attachment); }) .catch(error => { //debugger; console.log(error); }); ``` }) If more than 1 button are clicked at the same time, 2 DownloadFileAction actions will be dispatched Howerver, download_attachment$ effect only listen for one which is downloaded first and then return DownloadAttachmentSuccessAction, thus the other downloading files will not be finished Is there any solution or workaround ? Your idea is much appreciated