104 lines
3.0 KiB
JavaScript
104 lines
3.0 KiB
JavaScript
/**
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* The MIT License (MIT)
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*
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* Copyright (c) 2015 Jordan Thomas
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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"use strict";
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/**
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* Returns the similarity of the given strings.
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*
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* @param a {string} a string
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* @param b {string} a string
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* @param caseSensitive {boolean} whether the calculation should be case-sensitive
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* @returns {number} the similarity of the given strings
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*/
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export const jaroWinkler = function (a, b, caseSensitive = true) {
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// Convert to lowercase if not case-sensitive
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if (!caseSensitive) {
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a = a.toLowerCase();
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b = b.toLowerCase();
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}
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if (a.length === 0 || b.length === 0) return 0;
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if (a === b) return 1;
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// Calculate difference
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const range = Math.floor(Math.max(a.length, b.length) / 2) - 1;
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const aMatches = [];
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const bMatches = [];
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let low;
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let high;
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let m = 0;
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// Find matches
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for (let i = 0; i < a.length; i++) {
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low = (i >= range) ? i - range : 0;
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high = (i + range <= b.length) ? (i + range) : (b.length - 1);
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for (let j = low; j <= high; j++) {
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if (aMatches[i] !== true && bMatches[j] !== true && a[i] === b[j]) {
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aMatches[i] = true;
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bMatches[j] = true;
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m++;
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break;
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}
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}
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}
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// Short-circuit if not matches found
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if (m === 0) return 0;
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// Count transpositions
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let k = 0;
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let numTrans = 0;
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for (let i = 0; i < a.length; i++) {
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if (aMatches[i] === true) {
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let j;
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for (j = k; j < b.length; j++) {
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if (bMatches[j] === true) {
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k = j + 1;
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break;
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}
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}
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if (a[i] !== b[j]) numTrans++;
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}
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}
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let weight = (m / a.length + m / b.length + (m - numTrans / 2) / m) / 3;
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let l = 0;
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const p = 0.1;
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if (weight > 0.7) {
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while (a[l] === b[l] && l < 4)
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l++;
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weight += l * p * (1 - weight);
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}
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return weight;
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};
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