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Added 'Fuzzy Match' operation

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n1474335 2021-02-12 13:51:51 +00:00
parent 5893ac1a37
commit 8ad18bc7db
9 changed files with 196 additions and 39 deletions
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98
src/core/lib/FuzzySearch.mjs → src/core/lib/FuzzyMatch.mjs
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@ -16,40 +16,72 @@
* Anurag Awasthi - updated to 0.2.0
*/
const SEQUENTIAL_BONUS = 15; // bonus for adjacent matches
const SEPARATOR_BONUS = 30; // bonus if match occurs after a separator
const CAMEL_BONUS = 30; // bonus if match is uppercase and prev is lower
const FIRST_LETTER_BONUS = 15; // bonus if the first letter is matched
export const DEFAULT_WEIGHTS = {
sequentialBonus: 15, // bonus for adjacent matches
separatorBonus: 30, // bonus if match occurs after a separator
camelBonus: 30, // bonus if match is uppercase and prev is lower
firstLetterBonus: 15, // bonus if the first letter is matched
const LEADING_LETTER_PENALTY = -5; // penalty applied for every letter in str before the first match
const MAX_LEADING_LETTER_PENALTY = -15; // maximum penalty for leading letters
const UNMATCHED_LETTER_PENALTY = -1;
leadingLetterPenalty: -5, // penalty applied for every letter in str before the first match
maxLeadingLetterPenalty: -15, // maximum penalty for leading letters
unmatchedLetterPenalty: -1
};
/**
* Does a fuzzy search to find pattern inside a string.
* @param {*} pattern string pattern to search for
* @param {*} str string string which is being searched
* @param {string} pattern pattern to search for
* @param {string} str string which is being searched
* @param {boolean} global whether to search for all matches or just one
* @returns [boolean, number] a boolean which tells if pattern was
* found or not and a search score
*/
export function fuzzyMatch(pattern, str) {
export function fuzzyMatch(pattern, str, global=false, weights=DEFAULT_WEIGHTS) {
const recursionCount = 0;
const recursionLimit = 10;
const matches = [];
const maxMatches = 256;
return fuzzyMatchRecursive(
pattern,
str,
0 /* patternCurIndex */,
0 /* strCurrIndex */,
null /* srcMatces */,
matches,
maxMatches,
0 /* nextMatch */,
recursionCount,
recursionLimit
);
if (!global) {
return fuzzyMatchRecursive(
pattern,
str,
0 /* patternCurIndex */,
0 /* strCurrIndex */,
null /* srcMatches */,
matches,
maxMatches,
0 /* nextMatch */,
recursionCount,
recursionLimit,
weights
);
}
// Return all matches
let foundMatch = true,
score,
idxs,
strCurrIndex = 0;
const results = [];
while (foundMatch) {
[foundMatch, score, idxs] = fuzzyMatchRecursive(
pattern,
str,
0 /* patternCurIndex */,
strCurrIndex,
null /* srcMatches */,
matches,
maxMatches,
0 /* nextMatch */,
recursionCount,
recursionLimit,
weights
);
if (foundMatch) results.push([foundMatch, score, [...idxs]]);
strCurrIndex = idxs[idxs.length - 1] + 1;
}
return results;
}
/**
@ -65,7 +97,8 @@ function fuzzyMatchRecursive(
maxMatches,
nextMatch,
recursionCount,
recursionLimit
recursionLimit,
weights
) {
let outScore = 0;
@ -110,7 +143,8 @@ function fuzzyMatchRecursive(
maxMatches,
nextMatch,
recursionCount,
recursionLimit
recursionLimit,
weights
);
if (matched) {
@ -134,16 +168,16 @@ function fuzzyMatchRecursive(
outScore = 100;
// Apply leading letter penalty
let penalty = LEADING_LETTER_PENALTY * matches[0];
let penalty = weights.leadingLetterPenalty * matches[0];
penalty =
penalty < MAX_LEADING_LETTER_PENALTY ?
MAX_LEADING_LETTER_PENALTY :
penalty < weights.maxLeadingLetterPenalty ?
weights.maxLeadingLetterPenalty :
penalty;
outScore += penalty;
// Apply unmatched penalty
const unmatched = str.length - nextMatch;
outScore += UNMATCHED_LETTER_PENALTY * unmatched;
outScore += weights.unmatchedLetterPenalty * unmatched;
// Apply ordering bonuses
for (let i = 0; i < nextMatch; i++) {
@ -152,7 +186,7 @@ function fuzzyMatchRecursive(
if (i > 0) {
const prevIdx = matches[i - 1];
if (currIdx === prevIdx + 1) {
outScore += SEQUENTIAL_BONUS;
outScore += weights.sequentialBonus;
}
}
@ -165,15 +199,15 @@ function fuzzyMatchRecursive(
neighbor !== neighbor.toUpperCase() &&
curr !== curr.toLowerCase()
) {
outScore += CAMEL_BONUS;
outScore += weights.camelBonus;
}
const isNeighbourSeparator = neighbor === "_" || neighbor === " ";
if (isNeighbourSeparator) {
outScore += SEPARATOR_BONUS;
outScore += weights.separatorBonus;
}
} else {
// First letter
outScore += FIRST_LETTER_BONUS;
outScore += weights.firstLetterBonus;
}
}