generated from ztimson/template
33 lines
1.1 KiB
JavaScript
33 lines
1.1 KiB
JavaScript
export function levenshtein(a, b) {
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const m = a.length, n = b.length;
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if (!m) return n;
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if (!n) return m;
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const dp = Array.from({length: m + 1}, (_, i) => [i, ...Array(n).fill(0)]);
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for (let j = 0; j <= n; j++) dp[0][j] = j;
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for (let i = 1; i <= m; i++) {
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for (let j = 1; j <= n; j++) {
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dp[i][j] = a[i - 1] === b[j - 1]
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? dp[i - 1][j - 1]
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: 1 + Math.min(dp[i - 1][j - 1], dp[i - 1][j], dp[i][j - 1]);
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}
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}
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return dp[m][n];
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}
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/** Normalized similarity in [0,1]: 1 - editDistance / maxLength. */
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export function similarity(a, b) {
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a = a.toLowerCase(); b = b.toLowerCase();
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return 1 - levenshtein(a, b) / Math.max(a.length, b.length, 1);
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}
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/** Compares `target` against one or more search terms; returns avg/max/per-term similarity. */
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export function fuzzyMatch(target, ...terms) {
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if (!terms.length) throw new Error('Requires at least 1 term to compare');
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const similarities = terms.map(t => similarity(target, t));
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return {
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avg: similarities.reduce((acc, s) => acc + s, 0) / similarities.length,
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max: Math.max(...similarities),
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similarities,
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};
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}
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