booleanAttributeKeyword static method

String? booleanAttributeKeyword(
  1. String? attrName,
  2. Object? value
)

The keyword of the boolean attribute attrName in value (hidden="until-found" -> 'until-found'), or null if value is a boolean value.

booleanAttributeKeyword('hidden', 'until-found');  // 'until-found'
booleanAttributeKeyword('hidden', 'Until-Found');  // 'until-found'
booleanAttributeKeyword('hidden', 'true');         // null
booleanAttributeKeyword('checked', 'until-found'); // null

Implementation

static String? booleanAttributeKeyword(String? attrName, Object? value) {
  if (attrName == null || value is! String) return null;
  var keywords = _booleanAttributesKeywords[attrName];
  if (keywords == null) return null;
  var keyword = value.trim().toLowerCase();
  return keywords.contains(keyword) ? keyword : null;
}