Last Updated: 19 Aug 2022 11:08 by ADMIN
R. J.
Created on: 12 Aug 2022 17:12
Type: Feature Request
Default Pager Messages (String Templates) not Exported for use in Custom `messagesMap` Function

Just as a first note, the documentation on how to write a custom `messagesMap` function for use in the `Pager` component is extremely vague. Without access to the KendoReact source code, it would have been near impossible.

First request: on the `GridProps` API page, the `pager` prop is defined as being the type "null" or `ComponentType<PagerProps>`. Please convert the text "ComponentType<PagerProps>" into a link to the `PagerProps` page. This will greatly aid in quickly linking to the appropriate documentation.

Second request (and the bulk of the feature request): please make (at least) the pager-related constants and default messages (string templates) available to consuming components. As of v5.4.0 of `@progress/kendo-react-data-tools`, the constants are exported from {kendo-react-private}/packages/datatools/src/messages/index.ts and they are consumed within the `Pager` (and subcomponents), but are not re-exported.

Not having access to the pager-related constants (`pagerInfo`, `pagerFirstPage`, `pagerPreviousPage`, `pagerNextPage`, `pagerLastPage`, `pagerItemPerPage`, `pagerPage`, `pagerOf` and `pagerTotalPages`) means it's a complete shot in the dark at how to write an override function to supply as the `messagesMap` prop. Not only that, but without access to the pager-related default messages (string templates) and given the way the `Pager`'s `render` method is written, we are unable to change just one or just a couple messages; we have to address all nine.

Right now in v5.4.0, the way the `Pager`'s `render` method is written, it simply checks to see if `messagesMap` is non-null (lines 214 through 223 of Pager.tsx, lines 38-43 of PagerInput.tsx and lines 36 and 37 of PagerPageSizes.tsx). This means that if we pass in a custom function for `messagesMap`, the custom function will be used to evaluate the message/string-template for `pagerFirstPage`, `pagerPreviousPage`, `pagerNextPage`, `pagerLastPage`, `pagerInfo`, `pagerPage`, `pagerOf`, `pagerTotalPages` and `pagerItemPerPage` (just in those three, aforementioned files). This means that we have to somehow know that `pagerInfo`, for example, will come through to the custom function as the string "pager.info" or that `pagerPage` will come through as "pager.page" so that the custom function knows which `messageKey` it's being passed so it can send out the object with the appropriate message/string-template as the object's `defaultMessage` property.

Instead, if the pager-related constants and default messages were exposed, we could very easily write a custom `messagesMap` function that could address any number of the nine default messages.

As an example, the Telerik/Kendo default string template for `pagerInfo` is "{0} - {1} of {2} items" that could be better scoped to the type of data the grid shows. Let's say the grid displays products and we'd like the pager to show "Displaying products 5 - 10 of 302" in the bottom right. If the pager-related constants and messages were exposed, this becomes a very simple task while not disturbing all other Telerik/Kendo default messages:

import React from 'react';
import { Grid, GridColumn, GridNoRecords, GridColumnMenuFilter } from '@progress/kendo-react-grid';
import { pagerInfo, pagerOf, messages as defaultPagerMessages, Pager } from '@progress/kendo-react-data-tools';

export default function MyComponent() {
    const customMessagesMap = messageKey  => {
        switch (messageKey) {
            case pagerInfo: return { messageKey, defaultMessage: 'Displaying products {0} - {1} of {2}' };
            default: return { messageKey, defaultMessage: defaultPagerMessages[messageKey] };

    const CustomPager = () => (

    return (
        <div className='my-component'>
            <Grid data={[...]} pager={CustomPager}>
                <GridColumn ... />
The ability to override the string-templates used by the Grid Pager has been made very easy, and is well-documented, in the other Kendo frameworks (UI for jQuery, UI for Angular and UI for ASP.NET MVC). We're struggling to understand why it seems to be such a "black box" in KendoReact.
1 comment
Posted on: 19 Aug 2022 11:08

Hello, R. J. Lewis,

As we constantly try to better our products we appreciate the given feedback. 

Thank you for the submitted feature request we will be monitoring it closely.

Regards, FilipProgress Telerik

The Premier Dev Conference is back! 

Coming to you live from Progress360 in-person or on your own time, DevReach for all. Register Today.