Choosing Between Client-Side and Server-Side Pagination in PrimeNG Table

The Pagination Performance Gap

When implementing a data table in PrimeNG, the primary technical decision is whether to handle pagination in the browser (Client-side) or on the API (Server-side). Choosing the wrong strategy leads to either a sluggish initial load that freezes the browser or a fragmented user experience plagued by network latency.

The core trade-off is between immediate interaction and memory efficiency. If your dataset is small, moving the logic to the server adds unnecessary complexity. If your dataset is large, loading it all into the browser will crash the DOM.

Comparison of Pagination Strategies

Feature	Client-Side (Standard)	Server-Side (Lazy)
Data Load	Entire dataset loaded once	Only current page loaded
Page Transitions	Instant (Local slice)	Network request required
Browser Memory	High (Proportional to data)	Low (Fixed per page)
Backend Requirement	Simple GET endpoint	Limit/Offset support
Recommended Limit	< 2,000 records	Unlimited / Large datasets

Engineering Trade-offs

Client-Side Pagination

In this mode, you pass the full array to the [value] property. PrimeNG handles the slicing and sorting internally. This is ideal for configuration tables or small lists where the user needs to sort and filter rapidly without waiting for a server response.

Risk: Loading more than 5,000 records into a client-side table can lead to significant DOM degradation, as the browser struggles to maintain the state of the large array in memory.

Server-Side (Lazy) Pagination

By setting the lazy property to true, you tell PrimeNG not to handle the data slicing. Instead, the component emits an event whenever the page, sort, or filter changes. You must then fetch the specific slice of data from your backend.

Requirement: You must provide the totalRecords property. Without the total count from the database, the paginator cannot calculate how many page buttons to render.

Implementation: Server-Side (Lazy) Loading

This example assumes PrimeNG 16+ and an Angular environment. To implement lazy loading, you must handle the onLazyLoad event.

Component Template

<p-table 
    [value]<= data 
    [lazy]<= true 
    (onLazyLoad)<= loadData 
    [paginator]<= true 
    [rows]<= 10 
    [totalRecords]<= totalRecords 
    [loading]<= loading
>
    <ng-template pTemplate="header"
    >
        <tr>
            <th>ID</th>
            <th>Name</th>
        </tr>
    </ng-template>
    <ng-template pTemplate="body" let-item
    >
        <tr>
            <td>{{item.id}}</td>
            <td>{{item.name}}</td>
        </tr>
    </ng-template>
</p-table>

TypeScript Logic

// Run in your component.ts file
import { TableLazyLoadEvent } from 'primeng/table';

export class DataListComponent {
  data: any[] = [];
  totalRecords: number = 0;
  loading: boolean = false;

  loadData(event: TableLazyLoadEvent) {
    this.loading = true;

    // event.first = index of the first record (offset)
    // event.rows = number of records per page (limit)
    
    this.dataService.getRecords(event.first, event.rows).subscribe({
      next: (response) => {
        this.data = response.data;
        this.totalRecords = response.total;
        this.loading = false;
      },
      error: () => (this.loading = false)
    });
  }
}

Verification and Diagnostics

To verify that your implementation is correctly utilizing server-side pagination rather than accidentally loading the full dataset:

1. Open the Browser Developer Tools (F12) and navigate to the Network tab.
2. Click a page number in the PrimeNG paginator.
3. Check: A new XHR/Fetch request should trigger.
4. Validate Payload: Inspect the request URL or body. It should contain parameters like offset=20&limit=10.
5. Validate Response: The response body should contain only the records for that specific page (e.g., 10 items), not the entire database collection.

Rollback Strategy

If you determine that the network latency of server-side pagination is harming the UX and your dataset is small enough to fit in memory, revert by:

• Removing the [lazy]="true" attribute.
• Removing the (onLazyLoad) event handler.
• Fetching the entire dataset in ngOnInit and assigning it to the [value] property.