@technobuddha/library/diceCoefficient/diceCoefficient.mjs

A large library of useful functions

import { compareStrings } from '../compareStrings';
/**
 * Compute the dice coefficient measure of similarity between two strings
 *
 * @param input The first string
 * @param compareTo The second string
 * @param __nameParameters see {@link Options}
 * @return a number from 0 (not similar) to 1 (equal) measuring the similarity
 */
export function diceCoefficient(input, compareTo, { caseInsensitive = false } = {}) {
    if (input.length <= 1 || compareTo.length <= 1)
        return compareStrings(input, compareTo, { caseInsensitive }) === 0 ? 1.0 : 0.0;
    const bg0 = biGrams(caseInsensitive ? input.toLowerCase() : input);
    const bg1 = biGrams(caseInsensitive ? compareTo.toLowerCase() : compareTo);
    let count = 0;
    for (const bg of bg0) {
        const pos = bg1.indexOf(bg);
        if (pos >= 0) {
            count += 1;
            bg1[pos] = null;
        }
    }
    return count * 2 / (bg0.length + bg1.length);
}
function biGrams(input) {
    const biGram = [];
    for (let i = 0; i < input.length - 1; ++i)
        biGram.push(input.slice(i, i + 2));
    return biGram;
}
export default diceCoefficient;