string-metric/dist/OptimalStringAlignment.js

Get string similarity in JavaScript or TypeScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.OptimalStringAlignment = void 0;
var utils_1 = require("./utils/utils");
var OptimalStringAlignment = /** @class */ (function () {
    function OptimalStringAlignment() {
    }
    OptimalStringAlignment.prototype.distance = 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 0;
        }
        var n = s1.length;
        var m = s2.length;
        if (n == 0) {
            return m;
        }
        if (m == 0) {
            return n;
        }
        var d = utils_1.createTwoDimensionalArray(n + 2, m + 2);
        for (var i = 0; i <= n; i++) {
            d[i][0] = i;
        }
        for (var j = 0; j <= m; j++) {
            d[0][j] = j;
        }
        var cost;
        for (var i = 1; i <= n; i++) {
            for (var j = 1; j <= m; j++) {
                cost = 1;
                if (s1.charAt(i - 1) == s2.charAt(j - 1)) {
                    cost = 0;
                }
                d[i][j] = this.min(d[i - 1][j - 1] + cost, // substitution
                d[i][j - 1] + 1, // insertion
                d[i - 1][j] + 1 // deletion
                );
                //transposition check
                if (i > 1 && j > 1
                    && s1.charAt(i - 1) === s2.charAt(j - 2)
                    && s1.charAt(i - 2) === s2.charAt(j - 1)) {
                    d[i][j] = Math.min(d[i][j], d[i - 2][j - 2] + cost);
                }
            }
        }
        return d[n][m];
    };
    OptimalStringAlignment.prototype.min = function (a, b, c) {
        return Math.min(a, Math.min(b, c));
    };
    return OptimalStringAlignment;
}());
exports.OptimalStringAlignment = OptimalStringAlignment;