setOptionalWords method

AlgoliaQuery setOptionalWords(List<String> value)

optionalWords

A list of words that should be considered as optional when found in the query.

Normally, in order for a record to match it must match all words in the query. By creating a list of optional words, you are also matching records that match only some of the words.

This impacts ranking as follows:

• records that match all words are ranked higher
• records that match only some words are ranked lower

Usage notes:

• This invariably leads to a larger response.
• This is a strategy to improve a response with little or no results.
• You don’t need to put commas between words. Each string will automatically be tokenized into words, all of which will be considered as optional.
• This parameter is often used in the context of empty or insufficient results.

Caveat

• If a query is four or more words AND all its words are optional, the default behavior of optionalWords changes.
  • The number of matched words needed for an object to be returned increases every time 1000 objects are found.
  • If optionalWords contains less than 10 optional words, the number of matched words required for a result increments by one.
  • From 10 optional words onwards, the number of matched words required increments by the number of optional words divided by 5 (rounded down). For example, for an 18 word query with all words optional, the number of matched words needed goes up by 3 for every 1000 results returned. (results 1-1000 require only one word, results 1001-2000 need four matched words, etc).

Source: Learn more

Implementation

AlgoliaQuery setOptionalWords(List<String> value) {
  assert(value.isNotEmpty, 'value can not be empty');
  assert(!_parameters.containsKey('optionalWords'));
  return _copyWithParameters(<String, dynamic>{'optionalWords': value});
}