DataManager for TypeScript/JavaScript - Complete Guide

Table of Contents

• Key Concepts
• 10 Adaptors Reference
• Navigation Guide
• Quick Start
• Common Error Handling

🛑 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

10 Adaptor Types (Decision Guide)

Data Binding Types

Local Binding
├─ Direct array: new DataManager({ json: data })
├─ JsonAdaptor explicit
└─ Client-side filtering instant

Remote Binding
├─ WebApiAdaptor: ASP.NET specific
├─ UrlAdaptor: Generic REST
├─ ODataAdaptor/V4: Protocol-based
└─ Server processes Query object

Query Operations

// Filter/Search
.where('field', 'operator', value)     // Single condition
.where(predicate)                        // Complex predicate

// Sort/Order
.sortBy('field')                         // Ascending
.sortByDescending('field')               // Descending
.orderBy('field')                        // Alias

// Pagination
.take(10)                                // Limit records
.skip(0)                                 // Offset

// Projection
.select(['field1', 'field2'])            // Column selection

// Relationships
.expand('relatedTable')                  // OData expand

// Grouping & Aggregation
.group('field')                          // Group by
.aggregate('sum', 'field')               // Calculate

10 Adaptors Reference

Decision Tree: Which Adaptor?

Does your data come from?
│
├─ JavaScript array in memory?
│  └─ JsonAdaptor
│
├─ Web Server / REST API?
│  ├─ ASP.NET Web API (backend specific)?
│  │  └─ WebApiAdaptor (Items/Count format)
│  ├─ Generic REST endpoint?
│  │  └─ UrlAdaptor (result/count format)
│  ├─ Need offline with server-side CRUD?
│  │  └─ RemoteSaveAdaptor
│  └─ Custom format (non-standard)?
│     └─ CustomDataAdaptor
│
├─ OData Service?
│  ├─ OData v3 (legacy)?
│  │  └─ ODataAdaptor
│  └─ OData v4 (modern)?
│     └─ ODataV4Adaptor (with expand)
│
├─ GraphQL Endpoint?
│  └─ GraphQLAdaptor
│
├─ Legacy ASP.NET ASMX?
│  └─ WebMethodAdaptor
│
└─ Custom/Proprietary?
   ├─ Custom request/response format?
   │  └─ CustomDataAdaptor
   └─ Need complete adaptor override?
      └─ CustomAdaptor

Documentation Navigation Guide

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

📄 Read: 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 & Setup

Read: Getting Started

• Installation (@syncfusion/ej2-data)
• Browser requirements
• First DataManager example
• Local array binding
• Remote API binding

📄 Understand the Concepts

Read: Overview

• What is DataManager?
• Key features
• When to use DataManager
• Architecture

📄 Data Binding (Local & Remote)

Read: Data Binding

• Local arrays with JsonAdaptor
• Remote APIs (REST, OData)
• Error handling (HTTP 0, 400, 401, 404, 500)
• Promise patterns (.then/.catch)
• Async/await examples
• Loading states

📄 Build Complex Queries

Read: Querying

• from() - specify resource
• where() - 15+ filter operators (equal, contains, startswith, greaterThan, etc.)
• select() - column projection
• orderBy/sortBy - multiple sort columns
• take/skip - pagination
• group() - data grouping
• aggregate() - sum, avg, count, min, max
• Complex predicate-based filtering

📄 CRUD: Insert, Update, Delete

Read: CRUD Operations

• insert() - single & batch records
• update() & remove() with keyField parameter
• remove() - delete by ID
• saveChanges() - batch mixed operations
• Error handling & validation
• Response formats (Items/Count, result/count)
• Conflict resolution

📄 All 10 Adaptors Explained

Read: Adaptors Guide

• Complete adaptor decision tree
• Each adaptor with:
  • When to use
  • Configuration example
  • Usage example
  • Backend response format
  • C# or JavaScript backend patterns
• Comparison matrix
• CORS configuration

📄 Middleware & Request Customization

Read: Applying Middleware Logic

• Pre-request middleware (add headers, tokens)
• Post-request middleware (transform responses)
• JWT authentication patterns
• Custom headers (static & dynamic)
• Request/response transformation
• Error handling with retry
• Middleware execution order

📄 Browser State Persistence

Read: State Persistence

• enablePersistence - save query state
• localStorage integration
• Excluding specific queries from persistence
• Reapplying saved state on reload

📄 Advanced Scenarios & Optimization

Read: Advanced Scenarios

• Offline mode (download once, filter client-side)
• Load-on-demand pagination
• Deferred execution (Promises)
• Async/await patterns
• Memory management
• Performance optimization
• Troubleshooting

📄 API References

Read: API - DataManager

• executeQuery() method
• executeLocal() method
• insert(), update(), remove()
• saveChanges() for batch operations

Read: API - Query

• All Query builder methods
• where(), select(), from(), group()
• take(), skip(), orderBy()
• aggregate(), expand()

Read: API - Deferred

• Promise-based async handling
• then(), catch(), finally()
• Error callbacks

Quick Start

Setup

import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';

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

Query Example

// Fetch with filtering & sorting
dataManager.executeQuery(
  new Query()
    .where('Freight', 'greaterThan', 30)
    .sortByDescending('OrderDate')
    .take(20)
).then((result) => {
  console.log('Orders:', result.result);
  console.log('Total:', result.count);
}).catch((error) => {
  console.error('Error:', error);
});

CRUD Operations

// Insert (data first, then tableName)
await dataManager.insert({ CustomerID: 'VINET', Freight: 32.50 }, 'Orders');

// Update (keyField, value object, tableName)
await dataManager.update('OrderID', 
  { OrderID: 10248, Freight: 45.50 }, 
  'Orders'
);

// Delete (keyField, keyValue, tableName)
await dataManager.remove('OrderID', 10248, 'Orders');

Common Error Handling

HTTP Status Codes

Error Handling Pattern

// Promise-based
dataManager.executeQuery(new Query())
  .then((result) => {
    // Success: result.result, result.count
  })
  .catch((error) => {
    if (error.status === 401) {
      console.error('Unauthorized - login required');
    } else if (error.status === 500) {
      console.error('Server error');
    } else {
      console.error('Error:', error.message);
    }
  });

// Async/Await
try {
  const result = await dataManager.executeQuery(new Query());
  console.log('Data:', result.result);
} catch (error) {
  console.error('Error status:', error.status);
}

10 Key Properties

const config = {
  url: 'api.example.com/orders',        // Remote endpoint
  json: localArray,                              // Local data array
  adaptor: new WebApiAdaptor(),                 // Protocol handler
  
  // Caching & Performance
  enableCache: true,                            // Enable result caching
  timeTillExpiration: 10 * 60 * 1000,          // Cache TTL (10 mins, default: no expiry)
  
  // Persistence
  enablePersistence: true,                      // Enable state persistence
  id: 'dataManager_1',                          // Persistence ID
  ignoreOnPersist: ['temp', 'debug'],          // Properties to exclude
  // HTTP headers
  crossDomain: true,                            // CORS enabled
  offline: false,                               // Offline mode
  timeZoneHandling: true                        // Timezone offset handling
};

Framework Variants

TypeScript

import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';

const dm = new DataManager({
  url: 'api.example.com/orders',
  adaptor: new WebApiAdaptor()
});

dm.executeQuery(new Query().take(10)).then((result) => {
  console.log(result.result);
});

JavaScript (ES6)

const { DataManager, WebApiAdaptor, Query } = require('@syncfusion/ej2-data');

const dm = new DataManager({
  url: 'api.example.com/orders',
  adaptor: new WebApiAdaptor()
});

dm.executeQuery(new Query().take(10)).then((result) => {
  console.log(result.result);
});