locutus/esm/powershell/string/insert.js

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

export function insert(str, startIndex, value) {
    //      discuss at: https://locutus.io/powershell/insert/
    // parity verified: PowerShell 7.4
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //       example 1: insert('HelloWorld', 5, ' ')
    //       returns 1: 'Hello World'
    //       example 2: insert('abcd', 0, 'X')
    //       returns 2: 'Xabcd'
    //       example 3: insert('abcd', 4, '!')
    //       returns 3: 'abcd!'
    const source = String(str);
    const start = Math.trunc(Number(startIndex));
    if (!Number.isFinite(start) || start < 0 || start > source.length) {
        throw new RangeError('insert(): startIndex out of range');
    }
    return source.slice(0, start) + String(value) + source.slice(start);
}