library_names

Name libraries using lowercase_with_underscores.

DO name libraries using lowercase_with_underscores.

Some file systems are not case-sensitive, so many projects require filenames to be all lowercase. Using a separating character allows names to still be readable in that form. Using underscores as the separator ensures that the name is still a valid Dart identifier, which may be helpful if the language later supports symbolic imports.

BAD:

library peg-parser;

GOOD:

library peg_parser;

The lint file_names can be used to enforce the same kind of naming on the file.

To enable the library_names rule, add library_names under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - library_names

If you're instead using the YAML map syntax to configure linter rules, add library_names: true under linter > rules:

linter:
  rules:
    library_names: true

Unless stated otherwise, the documentation on this site reflects Dart 3.6.2. Page last updated on 2025-01-27. View source or report an issue.