A portable Markdown library written in Dart. It can parse Markdown into HTML on both the client and server.
Play with it at dart-lang.github.io/markdown.
import 'package:markdown/markdown.dart';
void main() {
print(markdownToHtml('Hello *Markdown*'));
//=> <p>Hello <em>Markdown</em></p>
}
A few Markdown extensions, beyond what was specified in the original
Perl Markdown implementation, are supported. By default, the ones supported
in CommonMark are enabled. Any individual extension can be enabled by
specifying an Array of extension syntaxes in the blockSyntaxes
or
inlineSyntaxes
argument of markdownToHtml
.
The currently supported inline extension syntaxes are:
InlineHtmlSyntax()
- approximately CommonMark's
definition of "Raw HTML".The currently supported block extension syntaxes are:
const FencedCodeBlockSyntax()
- Code blocks familiar to Pandoc and PHP
Markdown Extra users.const HeaderWithIdSyntax()
- ATX-style headers have generated IDs, for link
anchors (akin to Pandoc's auto_identifiers
).const SetextHeaderWithIdSyntax()
- Setext-style headers have generated IDs
for link anchors (akin to Pandoc's
auto_identifiers
).const TableSyntax()
- Table syntax familiar to GitHub, PHP Markdown Extra,
and Pandoc users.For example:
import 'package:markdown/markdown.dart';
void main() {
print(markdownToHtml('Hello <span class="green">Markdown</span>',
inlineSyntaxes: [InlineHtmlSyntax()]));
//=> <p>Hello <span class="green">Markdown</span></p>
}
To make extension management easy, you can also just specify an extension set.
Both markdownToHtml()
and Document()
accept an extensionSet
named
parameter. Currently, there are four pre-defined extension sets:
ExtensionSet.none
includes no extensions. With no extensions, Markdown
documents will be parsed with a default set of block and inline syntax
parsers that closely match how the document might be parsed by the original
Perl Markdown implementation.
ExtensionSet.commonMark
includes two extensions in addition to the default
parsers to bring the parsed output closer to the CommonMark specification:
Block Syntax Parser
const FencedCodeBlockSyntax()
Inline Syntax Parser
InlineHtmlSyntax()
ExtensionSet.gitHubFlavored
includes five extensions in addition to the default
parsers to bring the parsed output close to the GitHub Flavored Markdown
specification:
Block Syntax Parser
const FencedCodeBlockSyntax()
const TableSyntax()
Inline Syntax Parser
InlineHtmlSyntax()
StrikethroughSyntax()
AutolinkExtensionSyntax()
ExtensionSet.gitHubWeb
includes eight extensions. The same set of parsers use
in the gitHubFlavored
extension set with the addition of the block syntax parsers,
HeaderWithIdSyntax and SetextHeaderWithIdSyntax, which add id
attributes to
headers and inline syntax parser, EmojiSyntax, for parsing GitHub style emoji
characters:
Block Syntax Parser
const FencedCodeBlockSyntax()
const HeaderWithIdSyntax()
, which adds id
attributes to ATX-style
headers, for easy intra-document linking.
const SetextHeaderWithIdSyntax()
, which adds id
attributes to
Setext-style headers, for easy intra-document linking.
const TableSyntax()
Inline Syntax Parser
InlineHtmlSyntax()
StrikethroughSyntax()
EmojiSyntax()
AutolinkExtensionSyntax()
You can create and use your own syntaxes.
import 'package:markdown/markdown.dart';
void main() {
var syntaxes = [TextSyntax('nyan', sub: '~=[,,_,,]:3')];
print(markdownToHtml('nyan', inlineSyntaxes: syntaxes));
//=> <p>~=[,,_,,]:3</p>
}
This package offers no features in the way of HTML sanitization. Read Estevão Soares dos Santos's great article, ["Markdown's XSS Vulnerability (and how to mitigate it)"], to learn more.
The authors recommend that you perform any necessary sanitization on the
resulting HTML, for example via dart:html
's NodeValidator.
This package contains a number of files in the tool
directory for tracking
compliance with CommonMark.
dart run tool/stats.dart --update-files
to update the
per-test results tool/common_mark_stats.json
and the test summary
tool/common_mark_stats.txt
.Check out the CommonMark source. Make sure you checkout a major release.
Dump the test output overwriting the existing tests file.
> cd /path/to/common_mark_dir
> python3 test/spec_tests.py --dump-tests > \
/path/to/markdown.dart/tool/common_mark_tests.json
Update the stats files as described above. Note any changes in the results.
Update any references to the existing spec by search for
https://spec.commonmark.org/0.30/
in the repository. (Including this one.)
Verify the updated links are still valid.
Commit changes, including a corresponding note in CHANGELOG.md
.