110 lines
3.2 KiB
JavaScript
110 lines
3.2 KiB
JavaScript
/**
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* Modified Dec 23 2021 by Cris Stringfellow
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* fuzzy.js v0.1.0
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* (c) 2016 Ben Ripkens
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* @license: MIT
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*/
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// NOTES
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/*
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* Whether or not fuzzy.js should analyze sub-terms, i.e. also
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* check term starting positions != 0.
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*
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* Example:
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* Given the term 'Halleluja' and query 'luja'
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*
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* Fuzzy.js scores this combination with an 8, when analyzeSubTerms is
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* set to false, as the following matching string will be calculated:
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* Ha[l]lel[uja]
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*
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* If you activate sub temr analysis though, the query will reach a score
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* of 10, as the matching string looks as following:
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* Halle[luja]
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*
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* Naturally, the second version is more expensive than the first one.
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* You should therefore configure how many sub terms you which to analyse.
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* This can be configured through fuzzy.analyzeSubTermDepth = 10.
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*/
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fuzzy.analyzeSubTerms = false;
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/*
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* How many sub terms should be analyzed.
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*/
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fuzzy.analyzeSubTermDepth = 10;
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fuzzy.highlighting = {
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before: '<em>',
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after: '</em>'
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};
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fuzzy.matchComparator = function matchComparator(m1, m2) {
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return (m2.score - m1.score != 0) ? m2.score - m1.score : m1.term.length - m2.term.length;
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};
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export default function fuzzy(term, query) {
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var max = calcFuzzyScore(term, query);
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var termLength = term.length;
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if (fuzzy.analyzeSubTerms) {
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for (var i = 1; i < termLength && i < fuzzy.analyzeSubTermDepth; i++) {
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var subTerm = term.substring(i);
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var score = calcFuzzyScore(subTerm, query);
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if (score.score > max.score) {
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// we need to correct 'term' and 'matchedTerm', as calcFuzzyScore
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// does not now that it operates on a substring. Doing it only for
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// new maximum score to save some performance.
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score.term = term;
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score.highlightedTerm = term.substring(0, i) + score.highlightedTerm;
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max = score;
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}
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}
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}
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return max;
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}
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function calcFuzzyScore(term, query) {
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var score = 0;
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var termLength = term.length;
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var queryLength = query.length;
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var highlighting = '';
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var ti = 0;
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// -1 would not work as this would break the calculations of bonus
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// points for subsequent character matches. Something like
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// Number.MIN_VALUE would be more appropriate, but unfortunately
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// Number.MIN_VALUE + 1 equals 1...
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var previousMatchingCharacter = -2;
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for (var qi = 0; qi < queryLength && ti < termLength; qi++) {
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var qc = query.charAt(qi);
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var lowerQc = qc.toLowerCase();
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for (; ti < termLength; ti++) {
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var tc = term.charAt(ti);
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if (lowerQc === tc.toLowerCase()) {
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score++;
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if ((previousMatchingCharacter + 1) === ti) {
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score += 5;
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}
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highlighting += fuzzy.highlighting.before +
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tc +
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fuzzy.highlighting.after;
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previousMatchingCharacter = ti;
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ti++;
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break;
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} else {
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highlighting += tc;
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}
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}
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}
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highlighting += term.substring(ti, term.length);
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return {
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score: score,
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term: term,
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query: query,
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highlightedTerm: highlighting
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};
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};
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