string-metric/dist/JaroWinkler.js

Get string similarity in JavaScript or TypeScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.JaroWinkler = void 0;
var utils_1 = require("./utils/utils");
var JaroWinkler = /** @class */ (function () {
    function JaroWinkler(threshold) {
        this.DEFAULT_THRESHOLD = 0.7;
        this.THREE = 3;
        this.JW_COEF = 0.1;
        this.threshold = threshold || this.DEFAULT_THRESHOLD;
    }
    JaroWinkler.prototype.similarity = function (s1, s2) {
        if (utils_1.isNullOrUndefined(s1)) {
            throw new Error('s1 must neither be null nor undefined');
        }
        if (utils_1.isNullOrUndefined(s2)) {
            throw new Error('s2 must neither be null nor undefined');
        }
        if (s1 === s2) {
            return 1;
        }
        var mtp = this.matches(s1, s2);
        var m = mtp[0];
        if (m === 0) {
            return 0;
        }
        var j = ((m / s1.length + m / s2.length + (m - mtp[1]) / m)) / this.THREE;
        var jw = j;
        if (j > this.threshold) {
            jw = j + Math.min(this.JW_COEF, 1.0 / mtp[this.THREE]) * mtp[2] * (1 - j);
        }
        return jw;
    };
    JaroWinkler.prototype.distance = function (s1, s2) {
        return 1 - this.similarity(s1, s2);
    };
    JaroWinkler.prototype.matches = function (s1, s2) {
        var max;
        var min;
        if (s1.length > s2.length) {
            max = s1;
            min = s2;
        }
        else {
            max = s2;
            min = s1;
        }
        var range = Math.max(Math.floor(max.length / 2) - 1, 0);
        var matchIndexes = Array(min.length);
        matchIndexes.fill(-1);
        var matchFlags = Array(max.length);
        var matches = 0;
        for (var mi = 0; mi < min.length; mi++) {
            var c1 = min[mi];
            for (var xi = Math.max(mi - range, 0), xn = Math.min(mi + range + 1, max.length); xi < xn; xi++) {
                if (!matchFlags[xi] && c1 === max[xi]) {
                    matchIndexes[mi] = xi;
                    matchFlags[xi] = true;
                    matches++;
                    break;
                }
            }
        }
        var ms1 = Array(matches);
        var ms2 = Array(matches);
        for (var i = 0, si = 0; i < min.length; i++) {
            if (matchIndexes[i] !== -1) {
                ms1[si] = min[i];
                si++;
            }
        }
        for (var i = 0, si = 0; i < max.length; i++) {
            if (matchFlags[i]) {
                ms2[si] = max[i];
                si++;
            }
        }
        var transpositions = 0;
        for (var mi = 0; mi < ms1.length; mi++) {
            if (ms1[mi] !== ms2[mi]) {
                transpositions++;
            }
        }
        var prefix = 0;
        for (var mi = 0; mi < min.length; mi++) {
            if (s1[mi] === s2[mi]) {
                prefix++;
            }
            else {
                break;
            }
        }
        return [matches, Math.floor(transpositions / 2), prefix, max.length];
    };
    return JaroWinkler;
}());
exports.JaroWinkler = JaroWinkler;