Boost Your React Grid with Middleware: Secure Headers, Role-Based Filters, and More

Enterprise-grade React apps like HR systems, e-commerce platforms, and analytics dashboards often deal with massive datasets and complex API interactions. Hardcoding logic like authentication, filtering, and formatting directly into components leads to bloated, error-prone code.

Middleware offers a centralized, scalable solution to intercept and transform API requests and responses before they reach the Grid.

Understanding Syncfusion DataManager Middleware

Middleware acts as an interceptor for API interactions:

• Pre-request middleware: Add headers and adjust payloads
• Post-response middleware: Filter, format, and transform data

Key features

• Maintainability: Centralized logic reduces duplication
• Security: Inject tokens and keys securely
• Performance: Minimize rendering overhead
• Flexibility: Adapt to localization, roles, and formatting
• Scalability: Handle large datasets efficiently

Middleware logic enables developers to manipulate data and headers at runtime, supporting tasks like authentication, transformation, and filtering with minimal changes to the Grid’s code.

Note: For more details, refer to Syncfusion’s User Guide on Applying Middleware Logic.

Step-by-step guide: Implementing Middleware for scalable React Grids

Step 1: Install dependencies

To enable Grid and DataManager functionality, install the required packages:

 npm install @syncfusion/ej2-react-grids @syncfusion/ej2-data 

Step 2: Configure DataManager with Middleware (E-commerce inventory dashboard example)

Let us consider an example of an inventory dashboard that displays real-time stock across warehouses.

Requirements

• Inject the API key for secure access
• Filter out-of-stock items
• Convert prices to the user’s preferred currency

Middleware ensures consistent filtering and formatting, reducing UI complexity.

Here’s a practical implementation for an E-Commerce Inventory Dashboard Example, demonstrating how to inject an API key and transform the response for a user-friendly inventory view using middleware logic.

// src/components/InventoryGrid.tsx
import React, { useMemo } from 'react';
import {
    GridComponent,
    ColumnsDirective,
    ColumnDirective,
    Inject,
    Page
} from '@syncfusion/ej2-react-grids';
import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';
const InventoryGrid = () => {
    const apiKey = 'your-api-key-here'; // Replace with API key from config
    const userCurrency = 'USD';         // Replace with user’s preferred currency from context
    const dataManager = useMemo(() => {
        const dm = new DataManager({
            url: 'https://api.store.com/inventory',
            adaptor: new WebApiAdaptor()
        });
        // Add API key to requests
        dm.applyPreRequestMiddlewares([
            async (context) => {
                context.request.headers['X-Api-Key'] = apiKey;
            }
        ]);

        // Filter and transform response
        dm.applyPostRequestMiddlewares([
            async (context) => {
                if (Array.isArray(context.response.result)) {
                    context.response.result = context.response.result
                        .filter((item: any) => item.stock > 0) // Show only in-stock items
                        .map((item: any) => ({
                            productId: item.id,
                            productName: item.name,
                            price: ( item.price * (userCurrency === 'USD' ? 1 : 0.85)).toFixed(2), // Convert to EUR if needed
                            stock: item.stock
                        }));
                    }
                }
            ]);
            return dm;
        }, [apiKey, userCurrency]);
        return (
            <GridComponent
                dataSource={dataManager}
                allowPaging={true}
                pageSettings={{ pageSize: 20 }}
                query={new Query().select(['productId', 'productName', 'price', 'stock'])}
>
            <ColumnsDirective>
                <ColumnDirective field="productId" headerText="Product ID" width="100" textAlign="Right" />
                <ColumnDirective field="productName" headerText="Product Name" width="150" />
                <ColumnDirective field="price" headerText="Price" width="100" format="C2" />
                <ColumnDirective field="stock" headerText="Stock" width="100" />
            </ColumnsDirective>
            <Inject services={[Page]} />
        </GridComponent>
    );
};
export default InventoryGrid;

Explanation

Let’s break down how this code works in practice, focusing on security, transformation, and performance.

• Pre-request Middleware: Adds an API key to the request headers to authentic API calls.
• Post-response Middleware: Filters out products that are out of stock and converts prices based on the user’s preferred currency.
• Optimization: Utilizes useMemo to avoid unnecessary re-instantiation of the DataManager, and Query to limit the payload to essential fields, boosting performance.

Testing and debugging Middleware

To ensure your middleware works as expected:

• Log context objects: Use console.log(context) inside middleware functions to inspect request and response data.
• Validate adaptor: Confirm you’re using WebApiAdaptor or a compatible custom adaptor to support middleware hooks.
• Handle edge cases: Use Array.isArray() to avoid errors like map is not a function when the response is not an array.
• Test role-based logic: Simulate different user roles (e.g., HR Admin vs. regular user) to verify conditional rendering.
• Monitor network calls: Use browser developer tools to confirm headers (e.g., Authorization) are applied correctly.

Best practices and optimization tips

You’ve seen middleware in action, now let’s make it reusable, maintainable, and performant across your entire

Middleware reusability

• Centralize logic middleware in a middleware.ts module for reuse across multiple DataManager instances.
• Organize functions by purpose (e.g., authMiddleware, transformResponseMiddleware) for better modularity.

React optimization

• Use useMemo to memoize DataManager instances, preventing re-creation on rerenders.
• Manage tokens, roles, or user preferences with useContext or state management libraries (e.g., Redux, Zustand).

Syncfusion performance

• Enable enablePersistence to cache Grid settings (pagination, sorting) locally.
• Use the Query class to fetch only required fields (select, take, skip) for optimized API calls.

Common pitfalls and solutions

Even with these benefits and best practices, hiccups happen. Let’s address common pitfalls head-on so you can avoid them.

Issue	Cause	Solution
context.request.headers is undefined	Incorrect adaptor used	Use WebApiAdaptor or extend a compatible adaptor.
context.response.result.map is not a function	API response is not an array	Validate with Array.isArray(context.response.result) before mapping.
Headers not applied	Pre-middleware not registered	Ensure applyPreRequestMiddlewares is called before Grid rendering.
Data not filtered correctly	Logic error in middleware	Log context. Response and test middleware logic with sample data.

Real-world applications: Middleware in action

Middleware shines in scenarios where consistent data transformation, security, or logic needs to be applied across API interactions. Here are two practical examples:

1. HR portal with role-based employee grid

Imagine you’re building an HR portal that pulls over 100,000 employee records. The key requirements include:

• Securing API calls using bearer tokens
• Hiding sensitive fields unless the user is an HR Admin
• Localizing date formats based on the user’s region

Why Middleware?

Middleware centralizes authentication and conditional logic, allowing your Grid components to stay clean, focused, and easy to maintain.

2. Analytics dashboard with dynamic metrics

You’re developing a BI dashboard that aggregates sales data from multiple APIs. The requirements are:

• Applying user-specific filters
• Normalizing timestamps across sources
• Aggregating metrics before rendering

Why Middleware?

It streamlines data transformation and ensures the output is consistent, relevant, and tailored to each user.

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Conclusion

Middleware in React Grid architecture isn’t just a pattern, it’s a practical solution for managing complex data flows, securing API interactions, and transforming responses at scale. By integrating middleware into the DataManager, developers can streamline authentication, apply role-based logic, and optimize performance without bloating component code.

Ready to transform your Syncfusion React Grid with middleware? Follow the step-by-step guide and examples above to implement secure, efficient, and scalable data handling for your enterprise applications.

Explore  Syncfusion’s User Guide on Applying Middleware Logic for more details. Start building robust, data-driven Grids today and streamline your development process!

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