VDataTable server-side itemsPerPage change without automatic page reset

Answer

Vuetify’s VDataTable does not provide a built‑in option to automatically reset the page when itemsPerPage changes. The component watches the prop and, when the watcher fires, calls its internal paginate() method which sets pagination.page to 1. If the watcher does not fire (e.g., because the prop value is unchanged by reference or you are using a .sync binding that bypasses the watch), the current page number is retained.

Confirmed facts

• VDataTable exposes itemsPerPage, page and sort as controllable props and emits the corresponding update:* events.
• The internal watcher for itemsPerPage triggers a pagination reset in Vuetify 2.x and the default VDataTable implementation.
• Community wrappers or custom implementations may only watch for a new reference (!==), so mutating the same numeric value does not fire the watcher and the page stays unchanged.

Steps for this case

1. Bind itemsPerPage to a local data property so you control when it changes:

   :items-per-page="localItemsPerPage"

2. When you need to update the value, do it via a method that assigns a new number to the local property (this will trigger the watcher).
3. Immediately after the assignment, use Vue.nextTick to read the server’s total count and adjust the page:

   this.$nextTick(() => {
     const lastPage = Math.max(1, Math.ceil(this.total / this.localItemsPerPage));
     if (this.pagination.page > lastPage) {
       this.pagination.page = lastPage;
     }
   });

4. If you prefer to keep the current page whenever it remains valid, skip the reset and only clamp when the computed last page is smaller than the current page.

Missing diagnostic detail

To confirm whether the watcher behaves as described, please specify the exact Vuetify/VDataTable version you are using (e.g., Vuetify 2.x with v‑data‑table, Vuetify 3.x VDataTable, or a community wrapper). The version determines whether the watcher fires on value changes or only on reference changes, which influences whether you need the manual nextTick clamp.