Bibliothecary

A string search library implementing typical operators found in academic databases (boolean operators, NEAR, wildcards). This library lies in the heart of Snowball.

Installation

npm i bibliothecary

Usage

import { Query } from 'bibliothecary';

const intro = "A string search library implementing typical operators found in academic databases (boolean operators, NEAR, wildcards)."

const results = new Query('academic AND search AND library').search(intro);
/* => [
  { term: 'academic', text: 'academic', start: 64, length: 8 },
  { term: 'search', text: 'search', start: 9, length: 6 },
  { term: 'lib*', text: 'library', start: 16, length: 7 }
]*/
const shouldBeFalse = new Query('academic AND search AND NOT library').search(intro); // => false

A quick primer on search operators

Strings

• word1 word2 matches strings that mentions any of word1 and word2.
• "word1 word2" matches strings that contains exactly the phrase "word1 word2".

Search operators

• word1 AND word2 matches strings that mentions both word1 and word2.
• word1 OR word2 matches strings that mentions any of word1 and word2.
• NOT word1 matches strings that does not mention word1 anywhere.
• word1 NEAR/n word2 requires that word1 and word2 are n words or less apart.
• word1 ONEAR/n word2 does the same as NEAR/n, while also requires word1 to appear before word2.

Wildcards

• ? matches any one letter, e.g., wor? matches word and work.
• * matches any number of letters, e.g., wor* matches word and worry.

Combining operators

• Operators can be combined freely, e.g., "word1 B" AND NOT "word1 word3" OR (word1 ONEAR/3 word4) AND word5.
• () can be used to group parts of the query.
• Note that NEAR and ONEAR must have string literals on both sides and not other operators. That is, word1 NEAR/3 word2 is OK, but (word1 AND word2) NEAR/3 word3 is not.

Operator priorities

• Operators have different priorities. For example, word1 OR word2 AND word3 will be interpreted as word1 OR (word2 AND word3), because AND has higher priority than OR.
• Operators priorities are ordered as such: ""?* > () > ONEAR > NEAR > NOT > AND > OR.

Similar projects

• @spaceavocado/librarian