gem-hunter
Language: JavaScript
Converts HTML strings directly into React components and provide a simple way to modify and replace the content.
A utility for converting HTML strings into React components. Converts standard HTML elements, attributes and inline styles into their React equivalents and provides a simple way to modify and replace the content.
npm install react-html-parser
# or
yarn add react-html-parserimport React from 'react'; import ReactHtmlParser, { processNodes, convertNodeToElement, htmlparser2 } from 'react-html-parser'; class HtmlComponent extends React.Component { render() { const html = '<div>Example HTML string</div>'; return <div>{ ReactHtmlParser(html) }</div>; } }
It is important to understand that this library should not be used as a direct replacement for using properly sanitized HTML and that it only provides the same level of protection that React does which does not provide 100% protection. All HTML should be properly sanitized using a dedicated sanitisation library (such as dompurify for node/js) before being passed to this library to ensure that you are fully protected from malicious injections.
Whilst React has a certain level of protection to injection attacks built into it, it doesn't cover everything, for example:
<iframe src="javascript:alert('xss')" /><a href="javascript:alert('xss')">click me</a>Click here to see these in action and how to protect yourself using dompurify in the browser.
Including a sanitizer as part of the library means it is making decisions for you that may not be correct. It is up to you to decide what level of sanitization you need and to act accordingly. Some users may already be sanitizing on the server or others may have specialized requirements that cannot be covered by a generic implementation.
Additionally, HTML sanitization is a hard thing to get right and even the most popular and actively developed sanitizers have vulnerabilities discovered from time to time. By leaving the sanitization outside of this library it gives users the ability to patch and deploy any fixes needed immediately instead of having to wait for a new version of this library to be released with the fix.
Takes an HTML string and returns equivalent React elements
import ReactHtmlParser from 'react-html-parser';
html: The HTML string to parseoptions: Options object
htmlparser2The transform function will be called for every node that is parsed by the library.
function transform(node, index)
node: The node being parsed. This is the htmlparser2 node object. Full details can be found on their project page but important properties are:
type (string): The type of node (tag, text, style etc)name (string): The name of the nodechildren (array): Array of children nodesnext (node): The node's next siblingprev (node): The node's previous siblingparent (node): The node's parentdata (string): The text content, if the type is textindex (number): The index of the node in relation to it's parentreturn null
Returning null will prevent the node and all of it's children from being rendered.
function transform(node) { // do not render any <span> tags if (node.type === 'tag' && node.name === 'span') { return null; } }
return undefined
If the function does not return anything, or returns undefined, then the default behaviour will occur and the parser will continue was usual.
return React element
React elements can be returned directly
import React from 'react'; function transform(node) { if (node.type === 'tag' && node.name === 'b') { return <div>This was a bold tag</div>; } }
Allows pre-processing the nodes generated from the html by htmlparser2 before being passed to the library and converted to React elements.
function preprocessNodes(nodes)
nodes: The entire node tree generated by htmlparser2.The preprocessNodes function should return a valid htmlparser2 node tree.
Processes a node and returns the React element to be rendered. This function can be used in conjunction with the previously described transform function to continue to process a node after modifying it.
import { convertNodeToElement } from 'react-html-parser';
node: The node to processindex (number): The index of the node in relation to it's parenttransform: The transform function as described aboveimport { convertNodeToElement } from 'react-html-parser'; function transform(node, index) { // convert <ul> to <ol> if (node.type === 'tag' && node.name === 'ul') { node.name = 'ol'; return convertNodeToElement(node, index, transform); } }
The library exposes the htmlparser2 library it uses. This allows consumers
to use it without having to add it as a separate dependency.
See https://github.com/fb55/htmlparser2 for full details.