dart-best-practices

Original：🇺🇸 English

Translated

General best practices for Dart development. Covers code style, effective Dart, and language features.

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Sourcekevmoo/dash_skills

Added on2026-02-16

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npx skill4agent add kevmoo/dash_skills dart-best-practices

SKILL.md Content

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Dart Best Practices

1. When to use this skill

Use this skill when:

Writing or reviewing Dart code.
Looking for guidance on idiomatic Dart usage.

2. Best Practices

Multi-line Strings

Prefer using multi-line strings (

'''

) over concatenating strings with

and

\n

, especially for large blocks of text like SQL queries, HTML, or PEM-encoded keys. This improves readability and avoids

lines_longer_than_80_chars

lint errors by allowing natural line breaks.

Avoid:

dart

final pem = '-----BEGIN RSA PRIVATE KEY-----\n' +
    base64Encode(fullBytes) +
    '\n-----END RSA PRIVATE KEY-----';

Prefer:

dart

final pem = '''
-----BEGIN RSA PRIVATE KEY-----
${base64Encode(fullBytes)}
-----END RSA PRIVATE KEY-----''';

Robust extractions of values from a Map with Switch Expressions

When parsing

Map

structures or JSON (e.g., from

jsonDecode

), use switch expressions with object patterns for deep validation and extraction. This is clearer and safer than manual

is

checks or

as

casts.

Avoid (Unsafe Access):

dart

final json = jsonDecode(stdout);
if (json is Map &&
    json['configuration'] is Map &&
    json['configuration']['properties'] is Map &&
    json['configuration']['properties']['core'] is Map) {
  return json['configuration']['properties']['core']['project'] as String?;
}
return null;

Prefer (Deep Pattern Matching):

dart

return switch (jsonDecode(stdout)) {
  {
    'configuration': {
      'properties': {'core': {'project': final String project}},
    },
  } =>
    project,
  _ => null,
};

This pattern cleanly handles deeply nested structures and nullable fields without the complexity of verbose

if-else

blocks or the risk of runtime cast errors.

Line Length

Avoid lines longer than 80 characters, even in Markdown files and comments. This ensures code is readable in split-screen views and on smaller screens without horizontal scrolling.

Prefer: Target 80 characters for wrapping text. Exceptions are allowed for long URLs or identifiers that cannot be broken.

dart-best-practices

NPX Install

Tags

SKILL.md Content

Dart Best Practices

1. When to use this skill

2. Best Practices

Multi-line Strings

Robust extractions of values from a Map with Switch Expressions

Line Length