toPhrases method
Returns a list of unique phrases from the terms in the collection.
Splits each unique term at white-space and adds it to the set.
Implementation
Set<List<String>> toPhrases() {
final keywords = <List<String>>{};
for (var term in terms) {
term = term.normalizeWhitespace();
final kw = term.split(RegExp(r'\s+'));
if (kw.isNotEmpty) {
keywords.add(kw);
}
}
return keywords;
}