Switch from bigrams to trigrams for search #342
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This uses `Uint8Array` to represent byte arrays in the search index, reducing heap snapshot size in Firefox from 12.2 MB to 6.8 MB. Though Chrome appears to have a similar optimization already built in, so its heap snapshot marginally increases from 6.1 MB to 8.0 MB.
This is in preparation for switching from bigrams to trigrams, reducing the size of the subsequent diff.
Trigrams can provide more accurate search results than bigrams. For example, using bigrams, searching for "sel" would attempt to match the ngrams " s", "se", and "el". For the Rails API (at `7c65a4b83b583f4f`), the top result is `ActiveModel::Serializers` due to "Model" matching "el" and ":Serial" matching " s" and "se". However, using trigrams, "sel" would attempt to match " se" and "sel". In that case, for the Rails API, the top result is `ActiveRecord::QueryMethods#select`. The downside to using trigrams is that the search index increases from 2.9 MB to 8.6 MB. But the data compresses well, so when gzipped the size only increases from 474 kB to 670 kB. And browser heap snapshot size stays reasonably small, increasing from 6.8 MB to 11.1 MB in Firefox and 8.0 MB to 22.2 MB in Chrome.
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Trigrams can provide more accurate search results than bigrams. For example, using bigrams, searching for "sel" would attempt to match the ngrams " s", "se", and "el". For the Rails API (at
7c65a4b83b583f4f), the top result isActiveModel::Serializersdue to "Model" matching "el" and ":Serial" matching " s" and "se". However, using trigrams, "sel" would attempt to match " se" and "sel". In that case, for the Rails API, the top result isActiveRecord::QueryMethods#select.The downside to using trigrams is that the search index increases from 2.9 MB to 8.6 MB. But the data compresses well, so when gzipped the size only increases from 474 kB to 670 kB. And browser heap snapshot size stays reasonably small, increasing from 6.8 MB to 11.1 MB in Firefox and 8.0 MB to 22.2 MB in Chrome.