findByAbbreviation method Null safety

Option? findByAbbreviation(
  1. String abbr
)

Finds the option whose abbreviation is abbr, or null if no option has that abbreviation.

Implementation

Option? findByAbbreviation(String abbr) {
  for (var option in options.values) {
    if (option.abbr == abbr) return option;
  }
  return null;
}