jarontai/html2md

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html2md

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A library for converting HTML to Markdown in Dart. It supports CommonMark, simple table and custom converting rules.

Usage

A simple usage example:

import 'package:html2md/html2md.dart' as html2md;

main() {
    var html = '<h1>HTML2MD Demo</h1>';
    print(html2md.convert(html));
}

In flutter, you can use the flutter_markdown for rendering:

import 'package:html2md/html2md.dart' as html2md;
import 'package:flutter_markdown/flutter_markdown.dart';

build(BuildContext context) {
    // Caution!
    // This is not best practice, you should not call convert in build
    // and the converted markdown should put in state.
    var html = '<h1>HTML2MD Demo</h1>';
    var markdown = html2md.convert(html);
    return Markdown(data: markdown);
}

Config

You can config convert style by passing styleOptions to convert, elements that should be ignored also can be set with ignore. If you want to customize element converting, use custom rules!

html2md.convert(html,
    styleOptions: {'headingStyle': 'atx'},
    ignore: ['script'],
    rules: [Rule('custom')]);

The default and available style options:

Name	Default	Options
headingStyle	"setext"	"setext", "atx"
hr	"* * *"	"* * *", "- - -", "_ _ _"
bulletListMarker	"*"	"*", "-", "_"
codeBlockStyle	"indented"	"indented", "fenced"
fence	"```"	"```", "~~~"
emDelimiter	"_"	"_", "*"
strongDelimiter	"**"	"**", "__"
linkStyle	"inlined"	"inlined", "referenced"
linkReferenceStyle	"full"	"full", "collapsed", "shortcut"

Table support

Basic table converting is supported!

Html table source:

<table>
    <tr>
        <th>First Header</th>
        <th>First Header</th> 
    </tr>
    <tr>
        <td>Content Cell</td>
        <td>Content Cell</td>
    </tr>
    <tr>
        <td>Content Cell</td>
        <td>Content Cell</td>
    </tr>
</table>

The converted markdown source:

| First Header  | Second Header |
| ----- | ----- |
| Content Cell  | Content Cell  |
| Content Cell  | Content Cell  |

The converted markdown table:

First Header	Second Header
Content Cell	Content Cell
Content Cell	Content Cell

Custom Rules

Want to customize element converting? Write your rules!

Rule fields explaination

final String name; // unique rule name
final List<String>? filters; // simple element name filters, e.g. ['aside']
final FilterFn? filterFn; // function for building complex element filter logic
final Replacement? replacement; // function for doing the replacing
final Append? append; // function for appending content

Rule example - Convert the onebox section of discourse post to a link

<aside class="onebox">
  <header class="source">
      <img src="https://discoursesite/uploads/default/original/1X/test.png" class="site-icon" width="32" height="32">
      <a href="https://events.google.com/io/program/content?4=topic_flutter&amp;lng=zh-CN" target="_blank" rel="noopener">Google I/O 2021</a>
  </header>
</aside>

Rule(
  'discourse-onebox',
  filterFn: (node) {
    // Find aside with onebox class
    if (node.nodeName == 'aside' &&
        node.className.contains('onebox')) {
        return true;
    }
    return false;
  },
  replacement: (content, node) {
    // find the first a element under header
    var header = node.firstChild;
    var link = header!
        .childNodes()
        .firstWhere((element) => element.nodeName == 'a');
    var href = link.getAttribute('href');
    if (href != null && href.isNotEmpty) {
      return '[$href]($href)'; // build the link
    }
    return '';
  },
)

Test

dart run test

Features and bugs

Please file feature requests and bugs at the issue tracker.

Inspiration

html2md is basicly a simplify version of Node's turndown

License

Created from templates made available by Stagehand under a BSD-style license.