Option: matchAnyQueryToken (default false)

[charlotte-miller]

Bloodhound's tokenizer functions are a really powerful way to tune the search. Unfortunately this flexibility ends at SearchIndex.prototype.search. Currently datums must match ALL query-tokens (with no option to match ANY query-token). This pull request adds the option:

matchAnyQueryToken - By default a search result must match ALL query-tokens.
Instead, this option returns results that match ANY query-tokens.
Defaults to false

Inspired by Elasticsearch's MUST and SHOULD, matching ANY query-token opens up the possibility for more fuzzy search strategies. For more details see the tests and the following example:

var index = new SearchIndex({
  datumTokenizer: Bloodhound.tokenizers.obj.whitespace('value'),
  queryTokenizer: Bloodhound.tokenizers.whitespace,
  matchAnyQueryToken: true,
});

index.add({ value: 'food bar' });
index.search('fod bar'); // return { value: 'food bar' }

Note: Ideally this option could change from search-to-search. But I didn't want to clutter the Bloodhound#search api.

[core-system-dev]

LGTM

/cc @Apfeluser

[lenovouser]

Thanks a lot!