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Miscellaneous in JavaScript (ES5) RichTextEditor control

Placeholder

Specifies the placeholder for the Rich Text Editor’s content used when the Rich Text Editor body is empty through the placeholder property.

Through the e-rte-placeholder class to define our custom font family, font color, and styles to the placeholder text.

.e-richtexteditor .e-rte-placeholder {
    font-family: monospace;
}

The below sample demonstrates the placeholder option in Rich Text Editor.

Source
Preview
index.js
index.html
/**
 * Rich Text Editor placeholder sample 
 */
var defaultRTE = new ej.richtexteditor.RichTextEditor({
  placeholder:'Type Something' });
defaultRTE.appendTo('#defaultRTE');
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="defaultRTE">
            <p>The Rich Text Editor is WYSIWYG (&quot;what you see is what you get&quot;) editor useful to create and edit content, and return the valid <a href="https://ej2.syncfusion.com/home/" target="_blank">HTML markup</a> or <a href="https://ej2.syncfusion.com/home/" target="_blank">markdown</a> of the content</p>                
            <p><b>Key features:</b></p>
              <ul><li><p>Provides &lt;IFRAME&gt; and &lt;DIV&gt; modes</p></li>
              <li><p>Capable of handling markdown editing.</p></li>
              <li><p>Contains a modular library to load the necessary functionality on demand.</p></li>
              <li><p>Provides a fully customizable toolbar.</p></li>
              <li><p>Provides HTML view to edit the source directly for developers.</p></li>
              <li><p>Supports third-party library integration.</p></li>
              <li><p>Allows preview of modified content before saving it.</p></li>
              <li><p>Handles images, hyperlinks, video, hyperlinks, uploads, etc.</p></li>
              </ul>
        </div>
    </div>
    <style>
        .e-rte-quick-popup .e-rte-quick-toolbar .e-rotate-left::before {
            content: "\e76e";
        }
    
        .e-rte-quick-popup .e-rte-quick-toolbar .e-rotate-right::before {
            content: "\e726";
        }
    </style>


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

Character count

The Rich Text Editor automatically counts the number of characters in the content are while typing using the showCharCount property. The characters count displayed at the bottom of the editor. You can limit the number of characters in your content using the maxLength property. By default, the editor sets the characters limit value is infinity.

The character count color will be modified based on the characters in the Rich Text Editor.

Status Description
normal Till 70% of given maxLength count reach, character count color is black.
warning Once the number of character count in the Rich Text Editor reached 70% of given maxLength count, the character count color will be orange, indicating that, the Rich Text Editor value going to reach the maximum count.
error Once the number of character count in the Rich Text Editor reached 90% of given maxLength count, the character count color will be red, indicating that, the Rich Text Editor value reached the maximum count.

To create Rich Text Editor with showCharCount feature, inject the Count module to the RTE using the RichTextEditor.Inject(Count) method.

Source
Preview
index.js
index.html
var defaultRTE = new ej.richtexteditor.RichTextEditor({ showCharCount: true, maxLength: 2000 });
defaultRTE.appendTo('#defaultRTE');
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="defaultRTE">
            <p>The Rich Text Editor is WYSIWYG (&quot;what you see is what you get&quot;) editor useful to create and edit content, and return the valid <a href="https://ej2.syncfusion.com/home/" target="_blank">HTML markup</a> or <a href="https://ej2.syncfusion.com/home/" target="_blank">markdown</a> of the content</p>                
            <p><b>Key features:</b></p>
              <ul><li><p>Provides &lt;IFRAME&gt; and &lt;DIV&gt; modes</p></li>
              <li><p>Capable of handling markdown editing.</p></li>
              <li><p>Contains a modular library to load the necessary functionality on demand.</p></li>
              <li><p>Provides a fully customizable toolbar.</p></li>
              <li><p>Provides HTML view to edit the source directly for developers.</p></li>
              <li><p>Supports third-party library integration.</p></li>
              <li><p>Allows preview of modified content before saving it.</p></li>
              <li><p>Handles images, hyperlinks, video, hyperlinks, uploads, etc.</p></li>
              </ul>
        </div>
    </div>
    <style>
        .e-rte-quick-popup .e-rte-quick-toolbar .e-rotate-left::before {
            content: "\e76e";
        }
    
        .e-rte-quick-popup .e-rte-quick-toolbar .e-rotate-right::before {
            content: "\e726";
        }
    </style>


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

Code view

Rich Text Editor includes the ability for users to directly edit HTML code via Source View in the text area. If you made any modification in Source view directly, the changes will be reflected in the Rich Text Editor’s content. So, the users will have more flexibility over the content they have created.

Source
Preview
index.js
index.html
var defaultRTE = new ej.richtexteditor.RichTextEditor({ toolbarSettings: {
        items: ['SourceCode']
    },
    showCharCount: true,
    actionComplete: actionCompleteHandler });
defaultRTE.appendTo('#defaultRTE');
var myCodeMirror;

function mirrorConversion(e) {
    var id = defaultRTE.getID() + 'mirror-view';
    var textArea = defaultRTE.contentModule.getEditPanel();
    var mirrorView = defaultRTE.element.querySelector('#' + id);
    var charCount = defaultRTE.element.querySelector('.e-rte-character-count');
    if (e.targetItem === 'Preview') {
        textArea.style.display = 'block';
        mirrorView.style.display = 'none';
        textArea.innerHTML = myCodeMirror.getValue();
        charCount.style.display = 'block';
    }
    else {
        if (!mirrorView) {
            mirrorView = ej.base.createElement('div', { className: 'e-content' });
            mirrorView.id = id;
            textArea.parentNode.appendChild(mirrorView);
        }
        else {
            mirrorView.innerHTML = '';
        }
        textArea.style.display = 'none';
        mirrorView.style.display = 'block';
        renderCodeMirror(mirrorView, defaultRTE.value);
        charCount.style.display = 'none';
    }
}

function renderCodeMirror(mirrorView, content) {
    myCodeMirror = CodeMirror(mirrorView, {
        value: content,
        lineNumbers: true,
        mode: 'text/html',
        lineWrapping: true,
    });
}

function actionCompleteHandler(e) {
    if (e.targetItem && (e.targetItem === 'SourceCode' || e.targetItem === 'Preview')) {
        this.sourceCodeModule.getPanel().style.display = 'none';
        mirrorConversion(e);
    }
    else {
        setTimeout(function () { defaultRTE.toolbarModule.refreshToolbarOverflow(); }, 400);
    }
}
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
     <!--CodeMirror references-->
     <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.3.0/codemirror.js" type="text/javascript"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.3.0/mode/css/css.js" type="text/javascript"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.3.0/mode/xml/xml.js" type="text/javascript"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.3.0/mode/htmlmixed/htmlmixed.js" type="text/javascript"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.3.0/mode/javascript/javascript.js" type="text/javascript"></script>
     <link href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.3.0/codemirror.min.css" rel="stylesheet">
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
        <div id="defaultRTE">
            <p>The Rich Text Editor component is WYSIWYG (&quot;what you see is what you get&quot;) editor that provides the best user experience to create and update the content.Users can format their content using standard toolbar commands.</p>
            <p><b>Key features:</b></p>
              <ul><li><p>Provides <b>IFRAME</b> and <b>&gt;DIV</b> modes</p></li>
              <li><p>Capable of handling markdown editing.</p></li>
              <li><p>Contains a modular library to load the necessary functionality on demand.</p></li>
              <li><p>Provides a fully customizable toolbar.</p></li>
              <li><p>Provides HTML view to edit the source directly for developers.</p></li>
              <li><p>Supports third-party library integration.</p></li>
              <li><p>Allows preview of modified content before saving it.</p></li>
              <li><p>Handles images, hyperlinks, video, hyperlinks, uploads, etc.</p></li>
              </ul>
        </div>


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

Undo/Redo Manager

Undo and redo tools allow you to edit the text by disregard/cancel the recently made changes and restore it to previous state. It is a useful tool to restore the performed action which got changed by mistake. By default, upto 30 actions can be undo/redo in the editor.

To undo and redo operations, do one of the following:

  • Press the undo/redo button on the toolbar
  • Press the Ctrl + Z/Ctrl + Y combination on the keyboard

Customize the undo/redo step count using undoRedoSteps property. By default, undo/redo actions take 300ms time interval for store the action to the undoRedoManager. The time interval can be customized by using the undoRedoTimer.

Source
Preview
index.js
index.html
/**
 * Rich Text Editor Undo Redo sample 
 */
var defaultRTE = new ej.richtexteditor.RichTextEditor({ 
    height: 340,
    toolbarSettings: {
        items: ['Undo', 'Redo']},
    undoRedoSteps: 50,
    undoRedoTimer: 400
});
defaultRTE.appendTo('#defaultRTE');
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="defaultRTE">
            <p>The Rich Text Editor is WYSIWYG (&quot;what you see is what you get&quot;) editor useful to create and edit content, and return the valid <a href="https://ej2.syncfusion.com/home/" target="_blank">HTML markup</a> or <a href="https://ej2.syncfusion.com/home/" target="_blank">markdown</a> of the content</p>                
            <p><b>Key features:</b></p>
              <ul><li><p>Provides &lt;IFRAME&gt; and &lt;DIV&gt; modes</p></li>
              <li><p>Capable of handling markdown editing.</p></li>
              <li><p>Contains a modular library to load the necessary functionality on demand.</p></li>
              <li><p>Provides a fully customizable toolbar.</p></li>
              <li><p>Provides HTML view to edit the source directly for developers.</p></li>
              <li><p>Supports third-party library integration.</p></li>
              <li><p>Allows preview of modified content before saving it.</p></li>
              <li><p>Handles images, hyperlinks, video, hyperlinks, uploads, etc.</p></li>
              </ul>
        </div>
    </div>
    <style>
        .e-rte-quick-popup .e-rte-quick-toolbar .e-rotate-left::before {
            content: "\e76e";
        }
    
        .e-rte-quick-popup .e-rte-quick-toolbar .e-rotate-right::before {
            content: "\e726";
        }
    </style>


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

Prevention of cross-site scripting (XSS)

The Rich Text Editor allows the users to edit the content with security by preventing cross-site scripting (XSS). By default, provided built-in support to remove the elements from editor content, which cause XSS attack. The editor removes the elements based on the attributes if it is possible to execute script.

In the following sample, removed script tag and onmouseover attribute from content of the Rich Text Editor.

Source
Preview
index.js
index.html
/**
 * Prevention of XSS attack sample
 */
var rteValue = `<div onmouseover='javascript:alert(1)'>Prevention of Cross Sit Scripting (XSS) </div> <script>alert('hi')</script>`;

    var defaultRTE = new ej.richtexteditor.RichTextEditor({
       value: rteValue
    });
    defaultRTE.appendTo("#defaultRTE");
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="defaultRTE">
        </div>
    </div>


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

It is only applicable to editorMode as HTML.

Custom cross-site scripting

You can also filter the elements and attributes additionally, which cause the XSS attack through beforeSanitizeHtml event. Return the value from the event argument helper function to apply in the editor. To prevent the built-in support and make own cross-site scripting rules, set cancel argument to true.

The following sample demonstrates how to filter script tag from value.

Source
Preview
index.js
index.html
/**
 * Custom cross-site scripting sample
 */
var rteValue = `<div>Prevention of Cross Sit Scripting (XSS) </div> <script>alert('hi')</script>`;

var defaultRTE = new ej.richtexteditor.RichTextEditor({
  value: rteValue,
  beforeSanitizeHtml: (e) => {
    e.helper = (value) => {
      e.cancel = true;
      var temp = document.createElement('div');
      temp.innerHTML = value;
      var scriptTag = temp.querySelector('script');
      if (scriptTag) {
        ej.base.detach(scriptTag);
      }
      return temp.innerHTML;
    }
  }
});
defaultRTE.appendTo('#defaultRTE');
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="defaultRTE">
        </div>
    </div>


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

Resizable support

This feature allows the editor to be resized dynamically. The users can enable or disable this feature using the enableResize property in the Rich Text Editor. If enableResize is set to true, the Rich Text Editor component creates grip at the bottom right corner, which allows resizing the component in the diagonal direction. The following sample demonstrates the resizable feature.

Enabling the resizable support

To render the Rich Text Editor in the resizable mode, set the enableResize property to true. The above feature is built as module and hence the Resize module needs to be included in your application.

Source
Preview
index.js
index.html
/**
 * Rich Text Editor Resizable Sample
 */
import { RichTextEditor, Toolbar, Link, Image, HtmlEditor, QuickToolbar, Resize } from '@syncfusion/ej2-richtexteditor';
RichTextEditor.Inject(Toolbar, Link, Image, HtmlEditor, QuickToolbar, Resize);

let defaultRTE: RichTextEditor = new RichTextEditor({
    enableResize: true
});
defaultRTE.appendTo('#defaultRTE');
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-richtexteditor/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet">
     <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet">
    <link href="//cdn.syncfusion.com/ej2/ej2-splitbuttons/styles/material.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
    
    <div id="container">
        <div id="defaultRTE">
        </div>
    </div>


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

Specifying the Minimum and Maximum width and height for Resize

To have a restricted resizable area for the Rich Text Editor, you need to specify the min-width, max-width, min-height, and max-height CSS properties for the control’s wrapper element. By default, the control is capable of resizing upto the current viewport. The e-richtexteditor CSS class will be available in the component’s wrapper and can be used for applying the above mentioned styles.

.e-richtexteditor {
    min-width: 200px;
    max-width: 800px;
    min-height: 100px;
    max-height: 300px;
}
Source
Preview
index.js
index.html
/**
 * Rich Text Editor Resizable Sample
 */
import { RichTextEditor, Toolbar, Link, Image, HtmlEditor, QuickToolbar, Resize } from '@syncfusion/ej2-richtexteditor';
RichTextEditor.Inject(Toolbar, Link, Image, HtmlEditor, QuickToolbar, Resize);

let defaultRTE: RichTextEditor = new RichTextEditor({
    enableResize: true
});
defaultRTE.appendTo('#defaultRTE');
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 Rich Text Editor</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
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