p-multiselect: Performance fix when selecting all items (10000 records or more)

[ManojKChowdhury]

###Defect Fixes In scenarios when there are huge numbers of records in the multiselect dropdown, activating virtual scroll enables smooth open-close of the dropdown. But upon clicking the select-all checkbox:

• It takes around 13-14 seconds for the checkbox to be shown as selected and the dropdown to be usable again.
• The page becomes unusable during this duration.
• Closing the dropdown now and re-opening it with all items selected also takes a lot of time.
• De-selecting all items by clicking on the checkbox again takes considerable time.

Hence the changes in this commit aim to tackle this issue. Fixes #10695

[TUSHAR4541]

@ManojKChowdhury your code changes doesn't work for me to improve

• Initial loading time
• check all/uncheck all page unusable issue.

If possible create a fiddle for POC

[ManojKChowdhury]

It works for me, even with 10000 records! What are the options that you are setting on the p-dropdown?

[osamayawar]

We are facing similar issue and following are the options we are setting

<p-multiSelect
    [options]="options"
    [optionLabel]="optionLabel"
    [optionValue]="optionValue"
    [placeholder]="placeholder"
    [(ngModel)]="selectedOptions"
    [virtualScroll]="virtualScroll"
    [itemSize]="itemSize"
    ></p-multiSelect>

We have around 4000 records

[mertsincan]

Thanks a lot for the PR! But, please see my comment; https://github.com/primefaces/primeng/issues/10695#issuecomment-1190387255 Maybe, you can update your PR like in PrimeReact.

Best Regards,

[osamayawar]

@ManojKChowdhury can you please take a look or rather @mertsincan can you ask someone from your team to create a new PR for it? Would be of great help !!

[osamayawar]

Do we have an ETA for this fix?

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[github-actions[bot]]

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