htmlparser2-svelte

htmlparser2

A forgiving HTML/Svelte/XML/RSS parser. The parser can handle streams and provides a callback interface.

Extended version of htmlparser2 with Svelte syntax feature supporting, enabled by new options.

Additional features

• Support of JS expressions in tag attributes

<button type="button" on:click={() => handleButtonClick()}>
    Click to say hello
</button>

Installation

npm install htmlparser2-svelte

Usage

const htmlparser2 = require("htmlparser2-svelte");
const parser = new htmlparser2.Parser(
    {
        onopentag(name, attribs) {
            if (name === "script" && attribs.type === "text/javascript") {
                console.log("JS! Hooray!");
            }
        },
        ontext(text) {
            console.log("-->", text);
        },
        onclosetag(tagname) {
            if (tagname === "script") {
                console.log("That's it?!");
            }
        },
    },
    { decodeEntities: true }
);
parser.write(
    "Xyz <script type='text/javascript'>var foo = '<<bar>>';</ script>"
);
parser.end();

Output (simplified):

--> Xyz
JS! Hooray!
--> var foo = '<<bar>>';
That's it?!

Usage with streams

While the Parser interface closely resembles Node.js streams, it's not a 100% match. Use the WritableStream interface to process a streaming input:

const htmlparser2 = require("htmlparser2-svelte");
const parserStream = new htmlparser2.WritableStream(
    {
        ontext(text) {
            console.log("Streaming:", text);
        },
    },
    { decodeEntities: true }
);

const htmlStream = getHtmlStreamFromSomewhere();
htmlStream.pipe(parserStream).on("finish", () => console.log("done"));

Documentation

Read more about the parser and its options in the wiki.

Get a DOM

The DomHandler (known as DefaultHandler in the original htmlparser module) produces a DOM (document object model) that can be manipulated using the DomUtils helper.

The DomHandler, while still bundled with this module, was moved to its own module. Have a look at it for further information.

Parsing RSS/RDF/Atom Feeds

const feed = htmlparser2.parseFeed(content, options);

Note: While the provided feed handler works for most feeds, you might want to use danmactough/node-feedparser, which is much better tested and actively maintained.

Parsing Svelte HTML

const htmlparser2 = require("htmlparser2-svelte");
const parserStream = new htmlparser2.WritableStream(
    {
        ontext(text) {
            console.log("Streaming:", text);
        },
    },
    { 
        decodeEntities: true,
        curlyBracesInAttributes: true,
    }
);

const htmlStream = getHtmlStreamFromSomewhere();
htmlStream.pipe(parserStream).on("finish", () => console.log("done"));

Performance

After having some artificial benchmarks for some time, @AndreasMadsen published his htmlparser-benchmark, which benchmarks HTML parses based on real-world websites.

At the time of writing, the latest versions of all supported parsers show the following performance characteristics on Travis CI (please note that Travis doesn't guarantee equal conditions for all tests):

gumbo-parser   : 34.9208 ms/file ± 21.4238
html-parser    : 24.8224 ms/file ± 15.8703
html5          : 419.597 ms/file ± 264.265
htmlparser     : 60.0722 ms/file ± 384.844
htmlparser2-dom: 12.0749 ms/file ± 6.49474
htmlparser2    : 7.49130 ms/file ± 5.74368
hubbub         : 30.4980 ms/file ± 16.4682
libxmljs       : 14.1338 ms/file ± 18.6541
parse5         : 22.0439 ms/file ± 15.3743
sax            : 49.6513 ms/file ± 26.6032

How does this module differ from node-htmlparser?

This module started as a fork of the htmlparser module. The main difference is that htmlparser2 is intended to be used only with node (it runs on other platforms using browserify). htmlparser2 was rewritten multiple times and, while it maintains an API that's compatible with htmlparser in most cases, the projects don't share any code anymore.

The parser now provides a callback interface inspired by sax.js (originally targeted at readabilitySAX). As a result, old handlers won't work anymore.

The DefaultHandler and the RssHandler were renamed to clarify their purpose (to DomHandler and FeedHandler). The old names are still available when requiring htmlparser2, your code should work as expected.

Security contact information

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.

htmlparser2 for enterprise

Available as part of the Tidelift Subscription

The maintainers of htmlparser2 and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. Learn more.