Function search

Search for documents matching the given search query.

The result is a list of scored document IDs matching the query, sorted by descending score, and each including data about which terms were matched and in which fields.

Basic usage:

// Search for "zen art motorcycle" with default options: terms have to match
// exactly, and individual terms are joined with OR
search(searchIndex, 'zen art motorcycle')
// => [ { id: 2, score: 2.77258, match: { ... } }, { id: 4, score: 1.38629, match: { ... } } ]
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Restrict search to specific fields:

// Search only in the 'title' field
search(searchIndex, 'zen', { fields: ['title'] })
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Field boosting:

// Boost a field
search(searchIndex, 'zen', { boost: { title: 2 } })
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Prefix search:

// Search for "moto" with prefix search (it will match documents
// containing terms that start with "moto" or "neuro")
search(searchIndex, 'moto neuro', { prefix: true })
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Fuzzy search:

// Search for "ismael" with fuzzy search (it will match documents containing
// terms similar to "ismael", with a maximum edit distance of 0.2 term.length
// (rounded to nearest integer)
search(searchIndex, 'ismael', { fuzzy: 0.2 })
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Combining strategies:

// Mix of exact match, prefix search, and fuzzy search
search(searchIndex, 'ismael mob', {
 prefix: true,
 fuzzy: 0.2
})
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Advanced prefix and fuzzy search:

// Perform fuzzy and prefix search depending on the search term. Here
// performing prefix and fuzzy search only on terms longer than 3 characters
search(searchIndex, 'ismael mob', {
 prefix: term => term.length > 3
 fuzzy: term => term.length > 3 ? 0.2 : null
})
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Combine with AND:

// Combine search terms with AND (to match only documents that contain both
// "motorcycle" and "art")
search(searchIndex, 'motorcycle art', { combineWith: 'AND' })
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Combine with AND_NOT:

There is also an AND_NOT combinator, that finds documents that match the first term, but do not match any of the other terms. This combinator is rarely useful with simple queries, and is meant to be used with advanced query combinations (see later for more details).

Filtering results:

// Filter only results in the 'fiction' category (assuming that 'category'
// is a stored field)
search(searchIndex, 'motorcycle art', {
  filter: (result) => result.category === 'fiction'
})
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Wildcard query

Searching for an empty string (assuming the default tokenizer) returns no results. Sometimes though, one needs to match all documents, like in a "wildcard" search. This is possible by passing the special value wildcard as the query:

// Return search results for all documents
search(index, WILDCARD)
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Note that search options such as filter and boostDocument are still applied, influencing which results are returned, and their order:

// Return search results for all documents in the 'fiction' category
search(index, WILDCARD, {
  filter: (result) => result.category === 'fiction'
})
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Advanced combination of queries:

It is possible to combine different subqueries with OR, AND, and AND_NOT, and even with different search options, by passing a query expression tree object as the first argument, instead of a string.

// Search for documents that contain "zen" and ("motorcycle" or "archery")
search(searchIndex, {
  combineWith: 'AND',
  queries: [
    'zen',
    {
      combineWith: 'OR',
      queries: ['motorcycle', 'archery']
    }
  ]
})

// Search for documents that contain ("apple" or "pear") but not "juice" and
// not "tree"
search(searchIndex, {
  combineWith: 'AND_NOT',
  queries: [
    {
      combineWith: 'OR',
      queries: ['apple', 'pear']
    },
    'juice',
    'tree'
  ]
})
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Each node in the expression tree can be either a string, or an object that supports all SearchOptions fields, plus a queries array field for subqueries.

Note that, while this can become complicated to do by hand for complex or deeply nested queries, it provides a formalized expression tree API for external libraries that implement a parser for custom query languages.