PrimeNg datatable doesn't refresh

Question

Using Angular v2.4.8 and PrimeNg v1.1.4

I have a page with two components:

1. Dropzone, for uploading files
2. p-datatable to show the uploaded files

I configured Dropzone to send 5 files at a time and when it is finished with 5 files the event onDropZoneSendingMultiple is raised. When all files are uploaded onDropZoneQueueComplete is raised.

In both listeners I want to refresh the datatable which is in the second component. This is not working. I need to refresh the page to see the new files.

My HTML of the main page:

<div class="row" id="dropzoneContainer">
    <dropzone class="dropzone" #dz [config]="dropZoneConfig" 
              (error)="onDropZoneUploadError($event)"
              (sendingmultiple)="onDropZoneSendingMultiple($event)"
              (queuecomplete)="onDropZoneQueueComplete($event, dz);"
              (maxfilesreached)="onDropZoneMaxfilesReached($event)"
              (maxfilesexceeded)="onDropZoneMaxfilesExceeded"></dropzone>
</div>

<div class="row">
    <div class="col-md-12">
        <FilesList></FilesList>
    </div>
</div>

The Dropzone-component shows the dropzone. The FilesList shows the datatable. Part of the HTML:

<p-dataTable [hidden]="loading" [value]="files" selectionMode="single" (onRowSelect)="details($event)">

In my main ts-file I have:

@ViewChild(FilesListComponent)
public filesListComponent: FilesListComponent;

private reloadFileList() {
  this.filesListComponent.reload();
}

In my filelist ts I have

public files: File[];
public reload() {
    this.getFiles();
}
public getFiles() {
    this.fileService.getAll()
        .then(
        data => {
            this.files = data;
        });
}

getFiles is also called at page load. When I add console.log() statements I can see getFiles() is called and this.files is updated, but the table doesn't refresh.

Answer 1

For anyone still looking for the new syntax of adding records to an array that is bound to a primeng table

this.arrayRecords= [...this.arrayRecords, newObject];

Answer 2

Update: PrimeNG recently removed the DoCheck interface which was automatically detecting changes, see: https://www.primefaces.org/primeng-4-0-0-rc4-released/

The answer is to use the spread operator( [...arr] - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator ) to add items to your array instead of .push().

---

Original Answer: I had a similar issue which I solved using a slightly different approach. If you are using the same service to upload and retrieve your files you can use RxJS instead of listening to events across components.

On my services I want to reload across the app when I make a POST or PUT I use:

  private _shouldUpdateSource = new BehaviorSubject<boolean>(false);
  shouldUpdateObservable = this._shouldUpdateSource.asObservable();

In your POST and/or PUT methods

this.http.post(..).map( res => {this._shouldUpdateSource.next(true);});

Which allows you to subscribe to the fileService.shouldUpdateObservable in your components:

 this.shouldUpdateSub = this.fileService.shouldUpdateObservable
  .subscribe((shouldUpdate: boolean) => {
    if (shouldUpdate) {
      this.updateFiles();
    }
  });

This seems to be the best way to handle communication about a service between components I've seen/used.

-Edit- Here is the same concept in the official documentation:
https://angular.io/docs/ts/latest/cookbook/component-communication.html#!#bidirectional-service

-Edit 2- I ran into this issue again after updating to 4.0.0. FWIW, I ended up removing the PrimeNG Datatable, instead using a manual *ngFor and it worked fine. It seems that the PrimeNg documentation( https://www.primefaces.org/primeng/#/datatable ) tells you to:

"For example, use slice instead of splice when removing an item or use spread operator instead of push method when adding an item."

I'm not sure why they ask you to do this because it is contrary to what the official Angular documentation tells you to do but I believe it has something to do with why the [value] binding not working as you would expect.

Personally, I am moving away from PrimeNg in favor of the Covalent data table which has an explicit refresh() function: https://teradata.github.io/covalent/#/components/data-table

Answer 3

UPDATE: I took a better look at the documentation for p-dataTable, particularly the section titled Change Detection. I removed the [immutable]=false attribute work-around in the p-dataTable tag and instead I'm now getting the table to refresh by returning something like this when I modify the underlying array:

return myOriginalArray.slice();

ORIGINAL: I was having trouble with getting p-datatable to update/refresh when I removed an item from the underlying array used to populate the table. No clue as to why, but adding the following attribute to the p-datatable tag fixed things for me:

[immutable]=false

I'm using PrimeNG ^4.1.3