JSON RTE Serializer

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The JSON RTE Serializer package assists in converting the content within your JSON Rich Text Editor field between JSON and HTML formats. This means you can easily change your data from JSON format to HTML format for display purposes, and vice versa, for data storage or processing.
If you need to convert JSON to Markdown format, we offer the Markdown Serializer function. This function is specifically designed to transform your JSON data into Markdown, making it easier to handle text formatting for platforms that use Markdown.

Installation

To use JSON RTE Serializer with Node.js-based applications, you will need the following prerequisites:

- Node.js 10 or later

Install the json-rte-serializer package via npm using the following command:

``bash
npm install @contentstack/json-rte-serializer
`

Use Cases for JSON RTE Serializer

Let's look at a few code samples that display how we can convert data present in JSON format to HTML and vice versa.

Standard Conversion

For standard conversion scenarios, JSON RTE Serializer supports only the standard tags available in the JSON Rich Text Editor field. To use custom tags of your own, you can follow the Custom Conversion examples provided below.

$3

You can use the following JSON RTE Serializer code to convert your JSON RTE field data into HTML format.

`javascript
import { jsonToHtml } from "@contentstack/json-rte-serializer";

const htmlValue = jsonToHtml({
type: "doc",
attrs: {},
uid: "547a479c68824767ce1d9725852f042b",
children: [
{
uid: "767a479c6882471d9725852f042b67ce",
type: "p",
attrs: {},
children: [{ text: "This is HTML-formatted content." }],
},
],
});

console.log(htmlValue);
`

$3

The resulting HTML data will look as follows:

`HTML


This is HTML-formatted content.


`

$3

You can use the following JSON RTE Serializer code to convert HTML field data into JSON format.

`javascript
import { htmlToJson } from "@contentstack/json-rte-serializer";
const htmlDomBody = new DOMParser().parseFromString(
"

This is HTML-formatted content.

",
"text/html"
).body;
const jsonValue = htmlToJson(htmlDomBody);

console.log(jsonValue);
`
> _Note:_ The above code snippet would work only for JavaScript-powered frontend websites.

For Node.js-based applications, you can use the following code:
`javascript
const { htmlToJson } = require("@contentstack/json-rte-serializer")
const {JSDOM} = require('jsdom')

const dom = new JSDOM("

This is HTML-formatted content.

")
let htmlDoc = dom.window.document.querySelector('body')
const jsonValue = htmlToJson(htmlDoc)

console.log(jsonValue);
`

$3

The resulting JSON-formatted data will look as follows:

`JSON
{
"type":"doc",
"attrs":{},
"uid":"547a479c68824767ce1d9725852f042b",
"children":[{
"uid":"767a479c6882471d9725852f042b67ce",
"type": "p",
"attrs":{},
"children" : [{"text": "This is HTML-formatted content."}]
}]
}
`

$3

You can use the following JSON RTE Serializer code to convert your JSON RTE field data into Markdown format.

`javascript
import { jsonToMarkdown } from "@contentstack/json-rte-serializer";

const markdownValue = jsonToHtml({
type: "doc",
attrs: {},
uid: "547a479c68824767ce1d9725852f042b",
children: [
{
uid: "767a479c6882471d9725852f042b67ce",
type: "p",
attrs: {},
children: [
{ text: "This is Markdown-formatted content which has some " },
{ text: "BOLD", bold: true },
{ text: " text and some "},
{ text: "Italic", italic: true },
{ text: " text."}
]
},
],
});

console.log(markdownValue);
`

$3

The resulting Markdown data will look as follows:

`MARKDOWN

This is Markdown-formatted content which has some BOLD text and some Italic text.
`

Custom Conversion

For customized conversion scenarios, you can customize your JSON RTE Serializer code to allow the support for additional tags or element types in the JSON Rich Text Editor field. Pass an options field (optional) within the jsonToHtml or htmlToJson method to manipulate the working of the JSON RTE Serializer package as per your requirements.

$3

You can pass a custom parser method that will convert data for the mentioned JSON element type (e.g., social embed) to HTML format. Within the parsed options, the customElementTypes object parses block-level and inline elements (e.g., info panel), while the customTextWrapper object parses text formatting elements (e.g., bold, italics, font color, etc.). These options would take an object whose keys are types of elements and values are the parser functions that will be executed for that type.

The customElementTypes parser function provides the following arguments:

- attrs: The attributes that are passed against the node
- child: The nested elements of the current node
- jsonBlock: The entire JSON object that is currently being parsed

On the other hand, the customTextWrapper parser function provides the following arguments:

- child: The HTML string that specifies the child element
- value: The value passed against the child element

___

allowedEmptyAttributes

- Type: object
- Default: { img: ['alt'], reference: ['alt'] }

Specifies which empty attributes should be retained for specific HTML elements during the jsonToHtml conversion.
By default, the converter preserves the alt attribute for and reference (asset) elements, even when their values are empty.
This is particularly useful for ensuring semantic correctness and accessibility.

Use this option when you want to retain specific attributes with empty values during the conversion process.

___

addNbspForEmptyBlocks

- Type: boolean
- Default:false

When set to true, this option adds a non-breaking space (nbsp;) to empty blocks during the jsonToHtml conversion. This helps maintain the visual structure of the HTML output—especially useful for preserving spacing in editable content or content editors.

You can use the following customized JSON RTE Serializer code to convert your JSON RTE field data into HTML format.

`javascript
import { jsonToHtml } from "@contentstack/json-rte-serializer";
const jsonValue = {
type: "doc",
uid: "cfe8176d1ca04cc0b42f60b3047f611d",
attrs: {},
children: [
{
type: "p",
attrs: {},
uid: "6eae3c5bd7624bf39966c855543d954b",
children: [
{
type: "social-embed",
attrs: {
url: "https://twitter.com/Contentstack/status/1508911909038436365?cxt=HHwWmsC9-d_Y3fApAAAA",
style: {},
"redactor-attributes": {
url: "https://twitter.com/Contentstack/status/1508911909038436365?cxt=HHwWmsC9-d_Y3fApAAAA",
},
},
uid: "8d8482d852b84822a9b66e55ffd0e57c",
children: [{ text: "" }],
},
],
},
{
"type": "p",
"uid": "28c837c127504d3c85b9cb6d7099cb0b",
"attrs": {},
"children": [
{
"text": ""
}
]
},
{
type: "p",
attrs: {},
uid: "54a7340da87846dda28aaf622069559a",
children: [
{ text: "This " },
{ text: "is", attrs: { style: {} }, color: "red" },
{ text: " text." },
],
},
],
};
const htmlValue = jsonToHtml(
jsonValue,
// parser options
{
customElementTypes: {
"social-embed": (attrs, child, jsonBlock) => {
return ${child};
},
},
customTextWrapper: {
"color": (child, value) => {
return ${child};
},
},
allowedEmptyAttributes : {
"p": ["dir"],
"img" : ["width"]
},
addNbspForEmptyBlocks : true
}
);

console.log(htmlValue);
`

> _Note_: The specified custom parser's key must exactly match the element type. This includes the casing of the text.

$3

The resulting HTML data will look as follows:

`HTML


This is text.


`

$3

You can pass a custom parser method that will convert data for the mentioned HTML element type (e.g., ) to JSON format. Within the parsed options, the customElementTags object parses block-level and inline elements (e.g., info panel), while the customTextTags object parses text formatting elements (e.g., bold, italics, font color, etc.). These options would take an object whose keys are types of elements and values are the parser functions that will be executed for that type.

The parser function provides the el argument that references the element of the HTML node.

You can use the following customized JSON RTE Serializer code to convert your HTML RTE field data into JSON format.

`javascript
import { htmlToJson } from "@contentstack/json-rte-serializer";
const htmlDomBody = new DOMParser().parseFromString(


This is text.

,
"text/html"
).body;
const jsonValue = htmlToJson(htmlDomBody, {
customElementTags: {
"SOCIAL-EMBED": (el) => ({
type: "social-embed",
attrs: {
url: el.getAttribute("url") || null,
},
}),
},
customTextTags: {
"COLOR": (el) => {
return {
color: el.getAttribute("data-color"),
};
},
},
});

console.log(jsonValue);
`
> _Note:_ The above code snippet would work only for JavaScript-powered frontend websites.

For Node.js-based applications, you can use the following code:
`javascript
const { htmlToJson } = require("@contentstack/json-rte-serializer")
const {JSDOM} = require('jsdom')

const dom = new JSDOM(

This is text.

)
let htmlDoc = dom.window.document.querySelector('body')
const jsonValue = htmlToJson(htmlDoc, {
customElementTags: {
"SOCIAL-EMBED": (el) => ({
type: "social-embed",
attrs: {
url: el.getAttribute("url") || null,
},
}),
},
customTextTags: {
"COLOR": (el) => {
return {
color: el.getAttribute("data-color"),
};
},
},
});

console.log(jsonValue);
`

> _Note_: The custom parser's key must always be capitalized and exactly match the custom HTML tag.

$3

The resulting JSON-formatted data will look as follows:

`JSON
{
"type": "doc",
"uid": "cfe8176d1ca04cc0b42f60b3047f611d",
"attrs": {},
"children": [
{
"type": "p",
"attrs": {},
"uid": "6eae3c5bd7624bf39966c855543d954b",
"children": [
{
"type": "social-embed",
"attrs": {
"url": "https://twitter.com/Contentstack/status/1508911909038436365?cxt=HHwWmsC9-d_Y3fApAAAA",
"style": {},
"redactor-attributes": {
"url": "https://twitter.com/Contentstack/status/1508911909038436365?cxt=HHwWmsC9-d_Y3fApAAAA"
}
},
"uid": "8d8482d852b84822a9b66e55ffd0e57c",
"children": [
{
"text": ""
}
]
}
]
},
{
"type": "p",
"attrs": {},
"uid": "54a7340da87846dda28aaf622069559a",
"children": [
{
"text": "This "
},
{
"text": "is",
"attrs": {
"style": {}
},
"color": "red"
},
{
"text": " text."
}
]
}
]
}
`

Automatic Conversion

> _Note_: src url's provided for social-embeds and embed items will by default be uri encoded.

By default, the JSON Rich Text Editor field supports limited HTML tags within the editor. Due to this, the JSON RTE Serializer tool is not able to recognize each and every standard HTML tag.

To help the JSON RTE Serializer recognize and process additional tags that are commonly used across HTML, you can use the automatic conversion option. When using this option, you need to pass the allowNonStandardTags: true parameter within the jsonToHtml or htmlToJson method to manipulate the working of the JSON RTE Serializer package as per your requirements. When you pass this parameter, it customizes your JSON RTE Serializer code to allow the support for all standard HTML-recognized tags or element types in the JSON Rich Text Editor field.

$3

#### HTML Attribute Name and Value Sanitization


This project ensures that HTML attributes are properly validated and sanitized according to the W3C HTML specification. It validates attribute names based on the HTML standards and sanitizes attribute values to ensure correct rendering and security, particularly against cross-site scripting (XSS) vulnerabilities.

#### Attribute Name Guidelines

All HTML attribute names must conform to the W3C HTML specification. These guidelines specify the following rules:

- Printable ASCII Characters: Attribute names must consist only of printable ASCII characters.
- Case-Insensitive: Attribute names are case-insensitive, but lowercase is preferred for consistency.
- No Special Characters: Attribute names cannot contain spaces or special characters such as =, >, <, ", etc.
- Allowed Attributes: Attributes such as xmlns, aria-, data-, and others defined by HTML5 standards are allowed and must follow specific rules.

##### Important Note:
If an attribute name does not conform to these rules, the attribute will be dropped from the element.

#### Attribute Value Guidelines

The values of HTML attributes are sanitized to ensure proper rendering and to mitigate security risks, such as Cross-Site Scripting (XSS). This sanitization process involves replacing HTML entities (like <, >, &, etc.) with their corresponding characters and removing any invalid or unsafe characters.

Here are some common HTML entities and their replacements:

- < → <
- > → >
- & → &




---


You can pass the allowNonStandardTags: true parameter within the jsonToHtml method to allow the JSON RTE Serializer tool to recognize standard HTML tags or element types and convert them into JSON format.

You can use the following customized JSON RTE Serializer code to convert your JSON RTE field data into HTML format.


`js
import { jsonToHtml } from "@contentstack/json-rte-serializer";
const jsonValue = {
"type": "doc",
"uid": "cfe8176d1ca04cc0b42f60b3047f611d",
"attrs": {},
"children": [
{
"type": "hangout-module",
"attrs": {},
"children": [
{
"type": "hangout-chat",
"attrs": {
"from": "Paul, Addy"
},
"children": [
{
"type": "hangout-discussion",
"attrs": {},
"children": [
{
"type": "hangout-message",
"attrs": {
"from": "Paul",
"profile": "profile.png",
"datetime": "2013-07-17T12:02"
},
"children": [
{
"type": "p",
"attrs": {},
"children": [
{
"text": "Feelin' this Web Components thing."
}
]
},
{
"type": "p",
"attrs": {},
"children": [
{
"text": "Heard of it?"
}
]
}
]
}
]
}
]
},
{
"type": "hangout-chat",
"attrs": {},
"children": [
{
"text": "Hi There!"
}
]
}
]
}
]
};
const htmlValue = jsonToHtml(
jsonValue,
// parser options
{
allowNonStandardTypes: true
}
);

console.log(htmlValue);
`

$3

The resulting HTML data will look as follows:

`html


Feelin' this Web Components thing.

Heard of it?

Hi There!
`

$3

You can pass the allowNonStandardTags: true parameter within the htmlToJson method to allow the JSON RTE Serializer tool to recognize standard HTML tags or element types while converting the JSON data into HTML format.

You can use the following customized JSON RTE Serializer code to convert your HTML RTE field data into JSON format.


`js
import { htmlToJson } from "@contentstack/json-rte-serializer";
const htmlDomBody = new DOMParser().parseFromString(


Feelin' this Web Components thing.

Heard of it?

Hi There!,
"text/html"
).body;
const jsonValue = htmlToJson(htmlDomBody, {
allowNonStandardTags: true,
});

console.log(jsonValue);
`


$3

The resulting JSON-formatted data will look as follows:

`json
{
"type": "doc",
"uid": "cfe8176d1ca04cc0b42f60b3047f611d",
"attrs": {},
"children": [
{
"type": "hangout-module",
"attrs": {},
"children": [
{
"type": "hangout-chat",
"attrs": {
"from": "Paul, Addy"
},
"children": [
{
"type": "hangout-discussion",
"attrs": {},
"children": [
{
"type": "hangout-message",
"attrs": {
"from": "Paul",
"profile": "profile.png",
"datetime": "2013-07-17T12:02"
},
"children": [
{
"type": "p",
"attrs": {},
"children": [
{
"text": "Feelin' this Web Components thing."
}
]
},
{
"type": "p",
"attrs": {},
"children": [
{
"text": "Heard of it?"
}
]
}
]
}
]
}
]
},
{
"type": "hangout-chat",
"attrs": {},
"children": [
{
"text": "Hi There!"
}
]
}
]
}
]
}
``

Documentation

Refer to our JSON Rich Text Editor documentation for more information.

License

This project uses an MIT license. Refer to the LICENSE file for more information.