Querying in EJ2 JavaScript DataManager

18 Jun 202524 minutes to read

The Syncfusion EJ2 JavaScript DataManager offers a robust Query class that provides a fluent and intuitive API for building and executing data queries across various sources such as local collections, RESTful services, or OData endpoints.

With the Query class, you can build complex queries in a streamlined manner, enabling consistent and efficient data access across platforms. Whether you are working with client-side or server-side data, the Query class simplifies integration and empowers you to retrieve and shape data dynamically based on your application needs.

Using the Query class is like ordering food from a digital menu. You can filter for vegetarian items, sort them by price, and pick the top few and the system instantly gives you only the results you need, without going through everything manually.

How query processing works

The Query class in Syncfusion’s DataManager provides a fluent interface for defining and executing complex data operations, such as filtering, sorting, grouping, and paging. Each method in the Query class adds a logical layer of transformation, and the entire Query is processed through the executeQuery() method. This abstraction ensures efficient and optimized data handling, whether you’re working with local collections or remote data services.

The processing flow generally follows these steps:

  • Query definition:

Construct your Query using chained methods such as:

  1. from – Defines the data source.

  2. select – Specifies the fields to retrieve.

  3. where – Filters records based on conditions.

  4. sortBy – Sorts the data by one or more fields.

  5. take – Limits the number of records returned.

  • Execution:
    The Query is passed to the DataManager, which handles communication with the data source (e.g., OData service).

  • Adaptation:
    The adaptor converts the Query into a format compatible with the data source (e.g., REST, OData, Web API) and initiates the request.

  • Result handling:
    Once the response is received, the DataManager processes and maps the data to match the Query structure. The result can then be rendered or further processed in your application.

This modular and extensible approach simplifies data interactions, promotes maintainability, and supports dynamic data shaping tailored to your application’s needs.

Creating and executing queries

The Syncfusion Query class, available in the @syncfusion/ej2-data package, provides a fluent API for querying local or remote data. You can perform operations such as filtering, sorting, grouping, and aggregation on data before binding it to UI components like Grids, Lists, or Charts.

Queries are executed using the executeQuery or executeLocal methods of the DataManager, depending on whether you’re using a remote or local data source.

Method Usage Description
executeQuery Remote dataSource Sends the Query to the server or web service, which processes the Query and returns results asynchronously.
executeLocal Local dataSource Processes Query operations like filtering and sorting synchronously on data already in client memory, without server calls.

This section categorizes the available Query methods into three groups for ease of understanding:

  • Basic queries
  • Operation based queries
  • Custom queries

Basic query operations

1.select

Specifies the fields (columns) to retrieve from the data source.

let query = new ej.data.Query().select(['id', 'name'])

2.using

Sets a custom adaptor for the DataManager when executing a Query.

let query = new ej.data.Query().using(adaptorInstance);

3.from

Defines the data collection or resource name to target in the Query.

let query = new ej.data.Query().from('collectionName');

4.take

Retrieves only the specified number of records from the beginning of the result set.

let query = new ej.data.Query().take(5);

5.skip

Skips a given number of records from the beginning and returns the rest.

let query = new ej.data.skip(5);

The following example demonstrates how to specify a resource using from(), project fields using select(), apply a custom adaptor using using(), and implement pagination using skip() and take():

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(
    new ej.data.Query()
      .from('Orders')                                           // Specifies the target resource.
      .select(['OrderID', 'CustomerID', 'EmployeeID'])          // Project's specific fields.
      .using(new ej.data.ODataV4Adaptor())                      // Uses a custom adaptor for processing.
      .skip(8)                                                  // Skips the first 8 records.
      .take(8)                                                  // Takes the next 8 records.
  )
  .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
        <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Operation based queries

1.Eager loading navigation properties

The Syncfusion EJ2 JavaScript DataManager allows you to eagerly load related navigation properties using the expand method. This is especially useful for reduces the number of server requests by including related entities in one fetch. Enhances performance and consistency in master detail or hierarchical data scenarios. The navigation properties values are accessed using appropriate field names separated by dot(.) sign.

The following example demonstrates how to retrieve Orders along with related Employee’s First Name:

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${Employee.FirstName}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

var table = (document.getElementById('datatable'));

table.innerHTML = '<tr><th>OrderID</th><th>CustomerID</th><th>Employee Name</th></tr>';

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().expand('Employee').select(['OrderID', 'CustomerID', 'Employee.FirstName']).take(8))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

2.Sorting

Sorting helps organize data based on the values of a specific field, making it easier to view and analyze.

The Syncfusion EJ2 JavaScript DataManager allows you to perform sorting operations on data using thesortBy method. By default, sorting is in ascending order. To change the sort order, either you can specify the second argument of sortBy as descending or use the sortByDesc method.

The following example demonstrates how to sort data by CustomerID in descending order:

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().sortBy('CustomerID', 'descending').take(8))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet"> 
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Multi sorting can be performed by simply chaining the multiple sortBy methods.

Custom sorting

The Syncfusion EJ2 JavaScript DataManager allows custom sorting logic to be applied locally after retrieving the data. You need to retrieve a large set of order data, apply custom business rules for sorting.

This is particularly useful when you need to enforce complex business rules that go beyond basic field based sorting, such as prioritizing certain values, sorting based on derived fields, or applying multi level sort criteria dynamically.

The following example demonstrates how to fetch records from the server and manually sort the data by CustomerID in descending order.

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);
var table = document.getElementById('datatable');

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

new ej.data.DataManager({
  url: SERVICE_URI,
  adaptor: new ej.data.ODataV4Adaptor()
})
  .executeQuery(new ej.data.Query().take(50))  // Fetch a set of data.
  .then((e) => {
     // Custom sorting applied to CustomerID column.
    const sortedData = e.result.sort((a, b) => {
      if (a.CustomerID < b.CustomerID) return 1; 
      if (a.CustomerID > b.CustomerID) return -1; 
      return 0;
    });

    // Limit to the first 8 records after sorting.
    const topRecords = sortedData.slice(0, 8);

    // Append sorted records to the table.
    topRecords.forEach((data) => {
      table.appendChild(compiledFunction(data)[0]);
    });
  })
  .catch((error) => {
    console.error("Error fetching data: ", error);
  });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>              
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>

3.Filtering

The Syncfusion EJ2 JavaScript DataManager allows you to filter records using the where method. It supports simple and complex filtering scenarios, making it easy to retrieve a reduced and meaningful subset of data from a larger dataset.

The following example demonstrates how to filter records where EmployeeID is equal to 3:

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

let table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().where('EmployeeID', 'equal', 3).take(8))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Filter operators

Filter operators are generally used to specify the filter type. Syncfusion EJ2 JavaScript DataManager supports a variours of filter operators:

Operator Description
equal Matches exact value
notequal Excludes matching value
greaterthan Values greater than a specified value
greaterthanorequal Greater than or equal to a specified value
lessthan Less than a specified value
lessthanorequal Less than or equal to a specified value
startswith Starts with a substring
endswith Ends with a substring
contains Contains a substring

Use the following Query format to apply any filter condition by updating the field name, operator, and value:

let query = new ej.data.Query().where(field, operator, value);

The following example demonstrates how to filter records where the CustomerID contains the substring “VI”.

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

let table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().where('CustomerID', 'contains', 'VI').take(8)) // Filter records where CustomerID contains 'VI'.
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

These filter operators are used for creating filter Query using where method and Predicate class.

Build complex filter criteria using Predicate

Syncfusion EJ2 JavaScript DataManager allows you to apply complex filtering logic using the Predicate class. This is useful when multiple conditions need to be combined using logical operators like AND, OR, AND NOT, or OR NOT. Use Predicate when chaining .where() methods becomes unwieldy or insufficient for complex filtering rules.

The DataManager supports various Predicate methods:

Method Description
and Combines another condition with the current one using AND.
andNot Combines another condition using AND NOT.
or Combines another condition using OR.
orNot Combines another condition using OR NOT.
toJson Converts the predicate to a plain JavaScript object for serialization.
validate(record) Checks if a data record matches the predicate. Returns a boolean.
fromJson(json) Converts plain JavaScript objects back into Predicate instances. Useful for deserialization. 
var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

let table = (document.getElementById('datatable'));

//Building complex filter criteria using `Predicate`.
var predicate = new ej.data.Predicate('EmployeeID', 'equal', 3);
predicate = predicate.or('EmployeeID', 'equal', 2);

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().where(predicate).take(8))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

4.Searching

Syncfusion EJ2 JavaScript DataManager allows you to perform global or field specific searches across your dataset using the search method. It is used to filter the records from the entire data source based on the search parameter.

This method is ideal for implementing keyword based search experiences, especially in user driven scenarios like live search boxes or global table filters.

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

var table = (document.getElementById('datatable'));

new ej.data.DataManager(data)
    .executeQuery(new ej.data.Query().search('VI', ['CustomerID']))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="es5-datasource.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

You can search particular fields by passing the field name collection in the second argument of search method.

5.Grouping

The Syncfusion EJ2 JavaScript DataManager allows you to group records by one or more fields using the group method. Grouping is especially useful for reporting, data summarization, and categorization, where related records need to be logically organized based on shared field values.

The following example demonstrates how to group records by EmployeeID:

var template = '<tr><td>${field} - ${key}</td><td></td><td></td></tr>${for(item of items)}<tr><td>${item.OrderID}</td><td>${item.CustomerID}</td><td>${item.EmployeeID}</td></tr>${/for}';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().group('CustomerID').take(8))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Multiple grouping can be done by simply chaining the group method.

6.Paging

The Syncfusion EJ2 JavaScript DataManager allow you to fetch data one page at a time instead of loading the entire dataset at once. This is especially useful when working with large collections of data, helping your application stay fast and responsive.

You can Query paged data using page method. This allow you to Query particular set of records based on the page size and index.

The page method takes two arguments:

Parameter Type Description
pageIndex number The page number to retrieve
pageSize number The number of records to display per page

The following example demonstrate how to get the second page of data with 8 records per page:

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().page(2, 8))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <div id="Grid"></div>
        <table id="datatable" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

7.Aggregation

The Syncfusion EJ2 JavaScript DataManager allows you to compute summary values using the aggregate method. This is useful when you need to display totals, averages, counts, or other statistical summaries alongside your data. Aggregation is ideal for dashboards, reports, and summary views, where high level insights like minimum, maximum, or total values are needed.

The built-in aggregate types are as follows:

Aggregate Type Description
sum Adds all values in a field
average Calculates the average of values
min Finds the smallest value
max Finds the largest value
count Counts all values
truecount Counts true boolean values
falsecount Counts false boolean values

The following example demonstrates how to retrieve and display the minimum EmployeeID value from the first 5 records using the aggregate method:

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);
var footerFn = ej.base.compile('<tr><td></td><td></td><td>Minimum: ${min}</td></tr>');

const SERVICE_URI =  'https://services.odata.org/V4/Northwind/Northwind.svc/Orders/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().take(5).requiresCount().aggregate('min', 'EmployeeID'))
    .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
        table.appendChild(footerFn({ min: e.aggregates['EmployeeID - min'] })[0]);
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>

<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>

Custom queries

The Syncfusion EJ2 JavaScript DataManager provides several powerful methods in the Query class to build custom and dynamic queries. These are especially helpful when you want to manipulate the way data is fetched or shaped before execution.

The custom Query methods are as follows:

1.addParams(key, value)

The addParams method enables you to append custom parameters to the Query string. These parameters are included in the server request and are particularly useful for:

  • Sending dynamic user context (e.g., user ID, role, language).

  • Passing authentication tokens or API keys.

  • Applying server-side filters that are outside the standard Query schema.

The following example demonstrates how to add custom parameters to a Query request:

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query()
      .from('Orders')          
      .addParams('userId', '12345')
      .take(8)) 
  .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
        <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>

2.clone()

The Syncfusion EJ2 JavaScript DataManager provides the clone method, which allows you to create a deep copy of the current Query object. This is particularly useful when you want to reuse a base Query and apply slight modifications without altering the original.

This method is ideal for scenarios like tabbed views or pagination, where the base Query stays the same, but different tabs or pages require small changes.

The following example demonstrates how to clone a base Query, skip the first five records, and retrieve the next five orders.

var template =
  '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/';

var table = document.getElementById('datatable');

var baseQuery = new ej.data.Query()
    .from('Orders')
    .select(['OrderID', 'CustomerID', 'EmployeeID'])
    .take(5);
    
var clonedQuery = baseQuery.clone().skip(5);

new ej.data.DataManager({
  url: SERVICE_URI,
  adaptor: new ej.data.ODataV4Adaptor(),
})
  .executeQuery(clonedQuery)
  .then((e) => {
    e.result.forEach((data) => {
      table.appendChild(compiledFunction(data)[0]);
    });
  });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
        <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>

3.requiresCount(value: boolean)

The Syncfusion EJ2 JavaScript DataManager provides the requiresCount method to instruct the server to return the total number of available records in addition to the paginated result set.

This method is essential for implementing pagination or infinite scrolling in UI components like DataGrid or ListView, where the total number of items is required to:

  • Display accurate pagination controls.

  • Render the correct page numbers.

var template =
  '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/';

var table = document.getElementById('datatable');

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(new ej.data.Query().from('Orders').requiresCount(true).take(5)) 
    .then((e) => {
        console.log('Total Count:', e.count); // Count from server.
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
        <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>

4.range(start: number, end: number)

The Syncfusion EJ2 JavaScript DataManager provides the range(start, end) method to retrieve records within a specific index range. This method internally applies both skip() and take() logic, offering a concise and efficient way to fetch a slice of data.

This method is especially useful in scenarios such as infinite scrolling or virtual paging, where you need to load data in chunks rather than all at once. By specifying a start and end index, you can efficiently retrieve just the portion of data needed for display.

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/';

var table = (document.getElementById('datatable'));

new ej.data.DataManager({ url: SERVICE_URI, adaptor: new ej.data.ODataV4Adaptor })
    .executeQuery(
    new ej.data.Query()
      .from('Orders')          
      .range(5, 15)) 
      .then((e) => {
        (e.result).forEach((data) => {
            table.appendChild(compiledFunction(data)[0]);
        });
    });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
        <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>

5.setKey(field: string)

The Syncfusion EJ2 JavaScript DataManager includes the setKey(field: string) method to specify the primary key field for your dataset. This is crucial for enabling accurate CRUD operations such as update or delete where each record must be uniquely identifiable.

var template = '<tr><td>${OrderID}</td><td>${CustomerID}</td><td>${EmployeeID}</td></tr>';

var compiledFunction = ej.base.compile(template);

const SERVICE_URI = 'https://services.odata.org/V4/Northwind/Northwind.svc/';

var table = document.getElementById('datatable');

new ej.data.DataManager({
  url: SERVICE_URI,
  adaptor: new ej.data.ODataV4Adaptor(),
})
  .executeQuery(new ej.data.Query().from('Orders').setKey('OrderID').take(8))
  .then((e) => {
    e.result.forEach((data) => {
      table.appendChild(compiledFunction(data)[0]);
    });
  });
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript Grid Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-base/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-grids/styles/material.css" rel="stylesheet">
        <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-popups/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-calendars/styles/material.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/29.2.4/ej2-splitbuttons/styles/material.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/29.2.4/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id="container">
        <table id="datatable" border="1" class="e-table">
            <thead>
                <tr><th>Order ID</th><th>Customer ID</th><th>Employee ID</th></tr>
            </thead>
            <tbody>
            </tbody>    
        </table>        
    </div>
<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
</script>
<script src="index.js" type="text/javascript"></script>
</body></html>