Support full text indexes

[inexorabletash]

Either directly support full text indexes, or provide the primitives necessary to build them, which might include prefix-based searching, expression indexing, etc.

Imported from https://www.w3.org/2008/webapps/wiki/IndexedDatabaseFeatures

[inexorabletash]

i.e. may just be #33

[nolanlawson]

+1, big missing feature between WebSQL and IDB.

I agree this should be closed though in favor of #33 (w/ worklets). It ought to be out-of-scope to define particular stemmers for particular languages (e.g. Porter/English by default, as SQLite does). The worklet solution neatly allows e.g. Lunrjs to create their own. Folks will also inevitably want very complex stemmer functionality (e.g. "parse this field both as French and as English, index the union of all tokens") and such things should be solved in userland IMO.

Unsolved by #33 however: how to implement a scoring function, e.g. TF-IDF, DisMax, etc.

[inexorabletash]

If you're watching this issue...

One of the primitives necessary for building full text search on top of indexes is text segmentation. @littledan has a proposal for adding this to ECMA-402 (the ECMAScript Intl object). He'd love feedback:

• Proposal: https://github.com/littledan/Segmenter/blob/master/README.md
• Slides: https://docs.google.com/presentation/d/1X2zBU3bZ4ergVMWfubCsdnHFzeaDgqiTRJVgvNGjQBs/edit#slide=id.g17f706c31b_0_63

[EloB]

This is one of the big reason why I rather use WebSQL instead of Indexeddb.

[aphillips]

@nolanlawson and @inexorabletash have identified a couple of the challenges with implementing FTS: it's language sensitive, and open source provides imperfect solutions even for common languages. That's not an argument against it as a desirable feature, just a practical observation.

[inexorabletash]

TPAC 2019 Web Apps Indexed DB triage notes:

Valid use case, and also very complicated. Waiting on someone to come forward with a good design and POC, either high level or via primitives.

(Re: primitives - see #38)

[kaizhu256]

perhaps the best solution is to use sql.js instead? i'm skeptical about the usability and performance of an indexeddb solution compared to sqlite3.

[inexorabletash]

@kaizhu256 - take a look at https://github.com/fivedots/nativeio-explainer