cosmic_frontmatter

Description:

cosmic frontmatter

cosmic_frontmatter #
cosmic_frontmatter is a package that provides a simple way to parse the frontmatter of a markdown file.
Getting started #
To get started, you need to install the package by adding cosmic_frontmatter to your pubspec.yaml:
dependencies:
flutter:
sdk: flutter

cosmic_frontmatter: ^1.0.3
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Usage #
cosmic_frontmatter exports a parseFrontmatter function that takes a string (your markdown document) and a builder function. The builder function is called with the parsed frontmatter as a map.
This allows you to get typed frontmatter. Here's an example that uses json_serializable and freezed to generate a MockFrontmatter class:
import 'package:freezed_annotation/freezed_annotation.dart';

part 'mock_frontmatter.freezed.dart';
part 'mock_frontmatter.g.dart';

@freezed
class MockFrontmatter with _$MockFrontmatter {
const factory MockFrontmatter({
required String title,
required String author,
required String excerpt,
required String category,
required String date,
}) = _MockFrontmatter;

const MockFrontmatter._();

factory MockFrontmatter.fromJson(Map<String, dynamic> json) => _$MockFrontmatterFromJson(json);
}
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With the MockFrontmatter in place, you can parse the frontmatter of a markdown file:
const mockDocument = """
---
title: This is a test document
author: paul-halliday
excerpt: Learn how to use Markdown with Flutter at developer.school
category: Flutter
date: "2021-10-25"
---

You can learn how to use Markdown with Flutter at [developer.school](https://developer.school/tutorials/how-to-display-markdown-in-flutter).
""";

final mockFrontmatter = parseFrontmatter(
content: mockDocument,
frontmatterBuilder: (map) {
// Do anything you want with the `map`:

return MockFrontmatter.fromJson(map);
});
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This can then be used in your app however you want. Here's an example which merely displays the frontmatter on the screen, along-side the markdown body:
class _MyHomePageState extends State<MyHomePage> {
late Document<MockFrontmatter> document;

@override
void initState() {
super.initState();

document = parseFrontmatter(
content: mockDocument,
frontmatterBuilder: (map) => MockFrontmatter.fromJson(map),
);
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(document.frontmatter.title),
),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: Center(
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
ListTile(
contentPadding: EdgeInsets.zero,
title: const Text('Title'),
subtitle: Text(document.frontmatter.title),
),
ListTile(
contentPadding: EdgeInsets.zero,
title: const Text('Author'),
subtitle: Text(document.frontmatter.author),
),
ListTile(
contentPadding: EdgeInsets.zero,
title: const Text('Excerpt'),
subtitle: Text(document.frontmatter.excerpt),
),
ListTile(
contentPadding: EdgeInsets.zero,
title: const Text('Category'),
subtitle: Text(document.frontmatter.category),
),
ListTile(
contentPadding: EdgeInsets.zero,
title: const Text('Date'),
subtitle: Text(document.frontmatter.date),
),
Text(
'Content',
style: Theme.of(context).textTheme.headline6,
),
const SizedBox(
height: 10,
),
Expanded(
child: MarkdownBody(
data: document.body,
),
),
],
),
),
),
);
}
}
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MarkdownBody is a widget that displays markdown. It comes from the flutter_markdown package. You can find more information about it here.