locutus/esm/powershell/string/lastindexof.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

export function lastindexof(needle, haystack, startIndex) {
    //      discuss at: https://locutus.io/powershell/lastindexof/
    // parity verified: PowerShell 7.4
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //       example 1: lastindexof('o', 'Hello World')
    //       returns 1: 7
    //       example 2: lastindexof('x', 'Hello World')
    //       returns 2: -1
    //       example 3: lastindexof('o', 'Hello World', 6)
    //       returns 3: 4
    const source = String(haystack);
    const search = String(needle);
    if (startIndex === undefined) {
        return source.lastIndexOf(search);
    }
    return source.lastIndexOf(search, Math.trunc(Number(startIndex)));
}