Linter Rules

This page contains documentation for all Herb Linter rules.

Available Rules

• erb-no-empty-tags - Disallow empty ERB tags
• erb-no-output-control-flow - Prevents outputting control flow blocks
• erb-require-whitespace-inside-tags - Requires whitespace around erb tags
• html-anchor-require-href - Requires an href attribute on anchor tags
• html-aria-attribute-must-be-valid - Disallow invalid or unknown aria-* attributes.
• html-aria-role-heading-requires-level - Requires aria-level when supplying a role
• html-aria-role-must-be-valid - The role attribute must have a valid WAI-ARIA Role.
• html-attribute-double-quotes - Enforces double quotes for attribute values
• html-attribute-values-require-quotes - Requires quotes around attribute values
• html-boolean-attributes-no-value - Prevents values on boolean attributes
• html-img-require-alt - Requires alt attributes on img tags
• html-no-block-inside-inline - Prevents block-level elements inside inline elements
• html-no-duplicate-ids - Prevents duplicate IDs within a document
• html-no-duplicate-attributes - Prevents duplicate attributes on HTML elements
• html-no-nested-links - Prevents nested anchor tags
• html-tag-name-lowercase - Enforces lowercase tag names in HTML

Contributing

To add a new linter rule you can scaffold a new rule by running:

cd javascript/packages/linter

scripts/generate-rule

The script creates the documentation, rule stub, and test stub based on the GitHub issue (requires the linter label and a Rule name: [rule-name] line).

Alternatively, you can create one manually:

1. Create the rule class implementing the Rule interface
2. Add comprehensive tests in test/rules/
3. Add documentation in docs/rules/
4. Update the main linter to include the rule by default (if appropriate)

See html-tag-name-lowercase.ts for an example implementation.