locutus/esm/rust/str/rsplit_once.js

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

export function rsplit_once(delimiter, str) {
    //      discuss at: https://locutus.io/rust/rsplit_once/
    // parity verified: Rust 1.85
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Splits string on the last delimiter occurrence and returns [left, right] or null.
    //       example 1: rsplit_once('=', 'a=b=c')
    //       returns 1: ['a=b', 'c']
    //       example 2: rsplit_once('::', 'x::y::z')
    //       returns 2: ['x::y', 'z']
    //       example 3: rsplit_once(':', 'abc')
    //       returns 3: null
    const source = String(str);
    const value = String(delimiter);
    if (value === '') {
        return [source, ''];
    }
    const index = source.lastIndexOf(value);
    if (index < 0) {
        return null;
    }
    return [source.slice(0, index), source.slice(index + value.length)];
}