discussion/lib/string-similarity.js

Basic implementating to help altering between ongoing SpeechRecognition and intermittant SpeechSynthesis

// copypaste from https://github.com/aceakash/string-similarity/blob/master/src/index.js but typed
export function compareTwoStrings(first, second) {
    first = first.replace(/\s+/g, '');
    second = second.replace(/\s+/g, '');
    if (first === second)
        return 1; // identical or empty
    if (first.length < 2 || second.length < 2)
        return 0; // if either is a 0-letter or 1-letter string
    let firstBigrams = new Map();
    for (let i = 0; i < first.length - 1; i++) {
        const bigram = first.substring(i, i + 2);
        const count = firstBigrams.has(bigram)
            ? firstBigrams.get(bigram) + 1
            : 1;
        firstBigrams.set(bigram, count);
    }
    ;
    let intersectionSize = 0;
    for (let i = 0; i < second.length - 1; i++) {
        const bigram = second.substring(i, i + 2);
        const count = firstBigrams.has(bigram)
            ? firstBigrams.get(bigram)
            : 0;
        if (count > 0) {
            firstBigrams.set(bigram, count - 1);
            intersectionSize++;
        }
    }
    return (2.0 * intersectionSize) / (first.length + second.length - 2);
}
export function findBestMatch(mainString, targetStrings) {
    const ratings = [];
    let bestMatchIndex = 0;
    for (let i = 0; i < targetStrings.length; i++) {
        const currentTargetString = targetStrings[i];
        const currentRating = compareTwoStrings(mainString, currentTargetString);
        ratings.push({ target: currentTargetString, rating: currentRating });
        if (currentRating > ratings[bestMatchIndex].rating) {
            bestMatchIndex = i;
        }
    }
    const bestMatch = ratings[bestMatchIndex];
    return { ratings: ratings, bestMatch: bestMatch, bestMatchIndex: bestMatchIndex };
}
export class BestMatchResult {
}
export class Rating {
}