Add disjunctive facet search

[bidoubiwa]

disjunctiveFacetSearch changes how we handle multiple facet filters. See this spec to understand.

To understand better the following explanation, lets consider that we have two facets fields:

• color
  • red
  • blue
• genres
  • drama
  • action

Current behavior

When performing a search requiring that color is red and genres is drama, instant-meilisearch is going to perform ONE search requests with the following filters:

Only search request:

[["genres=drama"], ["color=red"]]

Unfortunately, this is not the expected behavior when using facets on most websites.

Disjunctive facet search

Using disjunctive facet search, we make as many requests as their are different facets filters.

For example, in our case above, we should have made 3 requests.

Search requests:

first request

[["genres:Adventure"], ["color:red"]],

Second request:

[["color:red"]],

Third request:

[["genres:Adventure"]],

The good news is that instantsearch provides us with the required requests. For example, if we ask for color blue and genres Adventure on a movie index, instantsearch provides us with the following objects:

( objects were reduced for readability )

[
  {
    "indexName": "movies",
    "params": {
      "facetFilters": [["genres:Adventure"], ["color:blue"]],
      "facets": ["genres","color"],
      "maxValuesPerFacet": 10,
      "query": "",
      "tagFilters": ""
    }
  },
  {
    "indexName": "movies",
    "params": {
      "facetFilters": [["color:blue"]],
      "facets": "genres",
      "hitsPerPage": 0,
      "maxValuesPerFacet": 10,
      "page": 0,
      "query": ""
    }
  },
  {
    "indexName": "movies",
    "params": {
      "facetFilters": [["genres:Adventure"]],
      "facets": "color",
      "hitsPerPage": 0,
      "maxValuesPerFacet": 10,
      "page": 0,
      "query": ""
    }
  },
]

We can then make a search request per element provided by instantsearch. Some elements are important to take into account:

• The first request is the default one, lets call it the hits request. It returns the hits and uses all the facet filters.
• The following requests, lets call them the facets requests are only used to provide the number of documents available for each facet
• The facets requests provide us with important field that must overide the current instantsearch context:
  • hitsPerPage is either 0 or 1 depending on the instantsearch plugin used. See corner cases
  • Page is always 0
  • The field facets is provided helping us knowing that this is a facets requests and not the hits request

Corner cases

• When using disjunctive facet search with a multi index search, all indexes must have the facets added to their filterableAttributes.
• disjunctive facet search is only used when the operator of refinementList is or
• Depending on the instantsearch environment the hitsPerPage value can be different when performing a facets request. For example in 'react-instantsearch-hooks-web' hitsPerPage is 0, but in react-instantsearch-dom hitsPerPage is 1

[engel-m]

I am not sure if the issue I am having is related to this, but for me a weird thing is that I am setting up my project exactly like the code in this example:

https://codesandbox.io/s/ms-is-mese9?fontsize=14&hidenavigation=1&theme=dark&file=/index.html:952-1057

But for me, disjunctive facetting does not work at all. When I select a facet, it filters correctly, but then removes all other options (which do have a hit count also), as if it were a non disjunctive facet. I can not figure out why the same code does not behave like in the example above.

Am I missing something in configuring the index maybe? Should a facet that is used with disjunctive always be stored as an array in the index f.e.? Or is this an issue with refinementList in the specific instant-meilisearch version (I am using 0.10.1)?

[bidoubiwa]

Hey @engel-m, are you using the current release of instant-meilisearch or this branch ? #888

[engel-m]

@bidoubiwa Update on this:

I have the problem with both branches.

I found out I was not able to get disjunctive facets to work because I had not configured keepZeroFacets to be set to true.

If I do, I can select multiple options for a facet without the rest disappearing. This would mean that when selecting a facet value, the result count of the other selectable values goes to zero.

[bidoubiwa]

Could you show me your configuration? keepZeroFacets is not working currently with multi-index/disjunctive facet search. I'm working on fixing that issue. But nonetheless, the disjunctive should at least react the same way as on the gifs in the PR.

Btw, did you set your operators on your refinement list to and, as disjunctive only works with or ?

[engel-m]

@bidoubiwa I tried every possible configuration combination there is, but with the exception of keepZeroFacets set to true and operator or , I can not even select multiple values for a facet. Once refined, the rest disappears.

Basically, I have the same problem as in this issue: https://github.com/meilisearch/instant-meilisearch/issues/789

But when I install your #888 branch it doesn't change anything for me, same issue as #789

[bidoubiwa]

Sorry, I may not have been clear. keepZeroFacets=true does not work currently on the multi-index search. See the todo at the end of the body of the PR https://github.com/meilisearch/instant-meilisearch/pull/888

I'm working on the fix :)

[bidoubiwa]

The beta it is released on npm :) Here

Could you try it ?

[pix2D]

Is there a way to force a particular facet is always taken into account? For example what if we always want to make sure the correct genre was returned, but then for other facets we don't care that much and they can fallback to less and less specific filters?

Our specific example is that we have a diets facet in our recipes app, and obviously if someone selects vegetarian we do not want to fall back to non-vegetarian recipes. But for all other facets it's fine.

[bidoubiwa]

Can the and operator solve your issue? Otherwise I would use the searchFunction or a wrapper around the instantMeilisearch.search method to change the value of facets/filters. This guide might help you

[jeremylynch]

Are we close to getting this one merged in?

[bidoubiwa]

It is available in a beta version. You can try it out already :) See release notes on how to try it.

It is up to date with the current latest release so trying it should not break anything

We are waiting for additional feedbacks to merge it

[MoustafaElsaghier]

can the same be done through APIs?

[sparkison]

Works great! 🎉 thanks so much for implementing this feature 🙏

[bidoubiwa]

Hey @MoustafaElsaghier, the multi-index search in the API is in consideration. We are discussing it here. Could you provide the reason why it would be useful to you there?

Thanks a lot for your feedback 🙏

[MoustafaElsaghier]

Hello @bidoubiwa, I'm looking for the disjunctive feature to be in API not a multi-index search

to be more clear, I need the disjunctive feature in the same index search same as the main GitHub issue in this thread

[jeremylynch]

Hi @bidoubiwa are we close to having this feature out of beta?

[bidoubiwa]

Hey! The release is planned around the 13th February

[bidoubiwa]

Released on the latest dist tag on npm :)