Syncfusion Angular DataManager

When to Use This Skill

Use this skill when you need to:

• Bind local JSON arrays to Angular components
• Connect Angular apps to remote REST, OData, or GraphQL services
• Implement querying, filtering, sorting, and paging on data
• Perform CRUD operations (Create, Read, Update, Delete) with data persistence
• Work offline and sync data when reconnected
• Transform and filter data using Query class
• Customize data communication with middleware
• Cache data to reduce server requests
• Handle different data source protocols automatically

This is your primary reference for:

• Any data operation in Syncfusion Angular components
• Universal data binding across all components
• Data source configuration and selection
• Async operations and error handling
• Performance optimization with caching

Component Overview

The DataManager is Syncfusion's universal data management module that acts as a bridge between your Angular application and any data source. It provides:

• 10 Built-in Adaptors — Support for JSON, OData v3/v4, REST, Web API, Web Methods, GraphQL, and custom sources
• Query Class — Powerful filtering, sorting, grouping, and paging API
• CRUD Operations — Insert, update, delete with automatic handling
• Promise-based Async — Native JavaScript Promise support
• Middleware Customization — Pre/post request hooks for authentication and transformation
• Offline Support — Work without server connection, sync when online
• Caching — Reduce server load and improve performance
• Type Safety — Full TypeScript definitions

🛑 MANDATORY HUMAN GATE: Adaptor Decision (Read This First)

This is the most critical rule in this skill. It cannot be skipped or bypassed.

When the user provides a service URL without explicitly naming the adaptor type, the agent MUST:

1. STOP code generation immediately
2. READ: references/adaptor-decision-gate.md (full file)
3. PRESENT the gate to the user using the template in that file
4. WAIT for explicit user confirmation of the adaptor choice
5. Only then proceed to generate DataManager code with the confirmed adaptor

Gate Trigger Conditions — Examples

📄 Full gate template, adaptor cheat sheet, disambiguation questions, and security rules: → references/adaptor-decision-gate.md

⚠️ Security & Trust Boundary

• This skill generates code only, the agent does not execute data operations or fetch remote endpoints — all DataManager interactions occur solely within the user's application at runtime.
• Generated code must treat all third-party API responses as untrusted input, never bind to unvalidated or user-provided URLs, and ensure authentication is enforced on all remote endpoints.

⚠️ Critical Security Requirements

When binding to remote services, you MUST implement these protections:

1. Use HTTPS only — never use unencrypted HTTP connections; encrypt all data in transit
2. Use string variables for URLs — assign endpoints to private string properties rather than hardcoding in markup; this enables centralized validation and easier maintenance
3. Validate and sanitize responses — implement server-side schema validation; reject unexpected response formats; map responses to strongly-typed models
4. Monitor remote calls — log all external API requests with timestamps, endpoints, and outcomes for security audit trails
5. Implement CORS securely — use specific trusted origins only; never use wildcard * in production; require HTTPS
6. Prevent indirect prompt injection attacks — verify endpoint ownership; implement request signing; validate response content types and schemas before consuming data

Third-party API responses can introduce security risks. Always verify endpoint legitimacy, authenticate requests, and validate data before binding to UI components.

Key Concepts & Trigger Keywords

Documentation and Navigation Guide

🛑 Adaptor Decision Gate (Human Approval — MANDATORY FIRST STEP for Remote URLs)

📄 Read: [references/adaptor-decision-gate.md](references/adaptor-decision-gate.md)

• When to trigger: User provides any service URL without explicitly naming the adaptor
• Gate presentation template (copy-paste ready)
• Full adaptor comparison table (ODataV4 / OData / WebAPI / URL / GraphQL / Custom)
• Adaptor quick-reference cheat sheets with code examples
• Disambiguation follow-up questions
• Security rules applied after gate confirmation
• Stage 1 & Stage 3 integration instructions (flags ambiguous URLs in component mapping JSON)
• Keywords that auto-resolve the gate (no user confirmation needed)

Getting Started

📄 Read: [references/getting-started.md](references/getting-started.md)

When to read: Starting new DataManager implementation, understanding package setup, learning TypeScript imports, configuring your first DataManager instance

Topics covered:

• Package installation and dependencies
• Module imports and TypeScript types
• Creating DataManager instances
• Difference between executeLocal and executeQuery
• Basic query execution patterns

Data Binding - Local and Remote

📄 Read: [references/data-binding.md](references/data-binding.md)

When to read: Deciding between client-side and server-side processing, implementing local JSON binding, connecting to remote APIs, understanding executeLocal vs executeQuery patterns

Topics covered:

• Local binding with json property
• Remote binding with url + adaptor
• Client-side vs server-side processing
• Promise-based async patterns
• Basic error handling

Querying and Filtering

📄 Read: [references/querying-and-filtering.md](references/querying-and-filtering.md)

When to read: Building queries, filtering by multiple conditions, sorting results, searching data, pagination, grouping records, advanced predicates

Topics covered:

• Query class fundamentals
• from() and select() methods
• where() with operators and predicates
• sortBy(), orderBy(), orderByDescending()
• take(), skip() for pagination
• search() method
• Grouping and aggregation

CRUD Operations

📄 Read: [references/crud-operations.md](references/crud-operations.md)

When to read: Adding new records, updating existing data, deleting records, batch operations, CRUD method parameters, persisting changes to server

Topics covered:

• Insert (add new records)
• Update (modify existing records)
• Remove (delete records)
• keyField in CRUD method parameters
• saveChanges() for batch operations
• Error handling and validation

10 Adaptors Guide - Complete Reference

📄 Read: [references/adaptors-guide.md](references/adaptors-guide.md)

When to read: Selecting appropriate data source, understanding adaptor differences, implementing specific adaptor patterns, working with different API types

Topics covered:

• JsonAdaptor — Local JavaScript arrays, no server calls
• ODataAdaptor — OData v3 service endpoints
• ODataV4Adaptor — OData v4 protocol support
• UrlAdaptor — Generic RESTful API endpoints
• WebApiAdaptor — ASP.NET Web API integration
• WebMethodAdaptor — ASP.NET Web Methods
• RemoteSaveAdaptor — Client-side queries + server-side CRUD
• GraphQLAdaptor — GraphQL query language support
• CustomDataAdaptor — Custom request/response handling
• CustomAdaptor — Extending built-in adaptors
• Adaptor decision tree
• Comparison matrix for all 10
• Code examples for each adaptor

Middleware Customization

📄 Read: [references/middleware-customization.md](references/middleware-customization.md)

When to read: Adding authentication headers, transforming requests/responses, logging API calls, implementing custom business logic

Topics covered:

• Pre-request middleware (applyPreRequestMiddlewares)
• Post-request middleware (applyPostMiddlewares)
• Custom headers (Authorization, etc.)
• Authentication patterns (Bearer tokens)
• Request/response transformation
• Error handling in middleware

Caching and Offline Mode

📄 Read: [references/caching-offline-mode.md](references/caching-offline-mode.md)

When to read: Improving performance with caching, working offline when server unavailable, implementing sync strategies, managing data persistence

Topics covered:

• Offline property configuration
• localStorage for data persistence
• Cache auto-clearing on CRUD
• Manual cache management
• Online/offline workflow
• Sync strategies

Advanced Features

📄 Read: [references/advanced-features.md](references/advanced-features.md)

When to read: Load on demand for large datasets, lazy loading relationships, pagination strategies, deferred operations, async/await patterns, memory management, state persistence

Topics covered:

• Load on demand pattern
• Lazy loading with expand()
• Pagination (client & server-side)
• Deferred operations with Promises
• Async/await patterns
• Promise.all() for parallel operations
• Error handling with status codes
• Memory management strategies
• Type safety with TypeScript
• State persistence patterns

How-To Recipes

📄 Read: [references/how-to-recipes.md](references/how-to-recipes.md)

When to read: Quick solutions for common scenarios, best practices, troubleshooting, pattern examples

Topics covered:

• Work in offline mode
• Send additional parameters
• Add custom headers
• Implement authentication
• Handle errors gracefully
• Common patterns
• Performance optimization tips
• Troubleshooting guides

Quick Start Example

Setup and Basic Data Binding

Step 1: Install Package

npm install @syncfusion/ej2-data

Step 2: Create Component

import { Component, OnInit } from '@angular/core';
import { DataManager, Query, JsonAdaptor, ReturnOption } from '@syncfusion/ej2-data';

@Component({
  selector: 'app-data-demo',
  templateUrl: './data-demo.component.html',
  styleUrls: ['./data-demo.component.css']
})
export class DataDemoComponent implements OnInit {
  public orders: object[];

  ngOnInit(): void {
    // Local data
    const data = [
      { OrderID: 10248, CustomerID: 'VINET', EmployeeID: 5, ShipCity: 'Reims' },
      { OrderID: 10249, CustomerID: 'TOMSP', EmployeeID: 6, ShipCity: 'Münster' },
      { OrderID: 10250, CustomerID: 'HANAR', EmployeeID: 4, ShipCity: 'Rio de Janeiro' }
    ];

    // Create DataManager with local data
    const dataManager = new DataManager({
      json: data,
      adaptor: new JsonAdaptor()
    });

    // Execute query
    this.orders = dataManager.executeLocal(
      new Query().where('EmployeeID', 'equal', 5)
    );
  }
}

Step 3: Display in Template

<table>
  <thead>
    <tr>
      <th>Order ID</th>
      <th>Customer ID</th>
      <th>Employee ID</th>
      <th>Ship City</th>
    </tr>
  </thead>
  <tbody>
    <tr *ngFor="let order of orders">
      <td>{{ order.OrderID }}</td>
      <td>{{ order.CustomerID }}</td>
      <td>{{ order.EmployeeID }}</td>
      <td>{{ order.ShipCity }}</td>
    </tr>
  </tbody>
</table>

Common Patterns

Remote Server with Promise

const dataManager = new DataManager({
  url: 'url',
  adaptor: new WebApiAdaptor()
});

// Using Promise
dataManager.executeQuery(new Query().take(10))
  .then((result: ReturnOption) => {
    this.orders = result.result;
  })
  .catch((error) => {
    console.error('Failed to fetch orders:', error);
  });

Async/Await Pattern

async fetchOrders(): Promise<void> {
  try {
    const result = await this.dataManager.executeQuery(
      new Query().take(10)
    );
    this.orders = result.result;
  } catch (error) {
    console.error('Error:', error);
  }
}

Filtering with Predicates

const query = new Query()
  .where('EmployeeID', 'equal', 5)
  .where('ShipCity', 'startswith', 'Rio');

const result = dataManager.executeLocal(query);

Server-side Operations

const query = new Query()
  .select(['OrderID', 'CustomerID', 'EmployeeID'])
  .where('EmployeeID', 'greaterThan', 3)
  .sortBy('OrderID')
  .take(10)
  .skip(0);

dataManager.executeQuery(query).then((result: ReturnOption) => {
  this.orders = result.result;
  this.totalRecords = result.count;
});

Key Properties Reference

Error Handling Best Practices

dataManager.executeQuery(query)
  .then((result: ReturnOption) => {
    if (result.result) {
      this.items = result.result;
    }
  })
  .catch((error: any) => {
    if (error.status === 401) {
      // Redirect to login
      console.error('Unauthorized');
    } else if (error.status === 403) {
      // Access denied
      console.error('Forbidden');
    } else if (error.status === 500) {
      // Server error
      console.error('Server error');
    } else if (error.status === 0) {
      // Network error
      console.error('Network error - check connectivity');
    }
  });

Common Use Cases

Use Case 1: Display Data Table

Start with [getting-started.md](references/getting-started.md) → [data-binding.md](references/data-binding.md) → [querying-and-filtering.md](references/querying-and-filtering.md)

Use Case 2: Implement CRUD Form

Start with [adaptors-guide.md](references/adaptors-guide.md) → [crud-operations.md](references/crud-operations.md) → [advanced-features.md](references/advanced-features.md)

Use Case 3: Work with Multiple Data Sources

Start with [adaptors-guide.md](references/adaptors-guide.md) (decision tree) → specific adaptor pattern → [middleware-customization.md](references/middleware-customization.md)

Use Case 4: Optimize Large Datasets

Start with [advanced-features.md](references/advanced-features.md) → [caching-offline-mode.md](references/caching-offline-mode.md) → [how-to-recipes.md](references/how-to-recipes.md)

TypeScript Type Safety

// Define your data model
interface Order {
  OrderID: number;
  CustomerID: string;
  EmployeeID: number;
  ShipCity: string;
}

// Use generics for type safety
const dataManager: DataManager<Order> = new DataManager({
  json: orders,
  adaptor: new JsonAdaptor()
});

// Typed results
const result = await dataManager.executeQuery(new Query());
const typedOrders: Order[] = result.result as Order[];

Performance Optimization Tips

1. Use proper adaptor — Select adaptor matching your backend
2. Filter early — Push filtering to server when possible
3. Enable caching — Reduce redundant server calls
4. Lazy load — Load data on demand for large datasets
5. Pagination — Limit records per request
6. Offline mode — Load once, work offline
7. Select columns — Fetch only needed fields