locutus/esm/golang/strconv/Atoi.js

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

export function Atoi(s) {
    //      discuss at: https://locutus.io/golang/strconv/Atoi
    // parity verified: Go 1.23
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Parses a decimal string and returns the integer value.
    //          note 1: Returns [value, null] on success, [0, error] on failure.
    //       example 1: Atoi('42')[0]
    //       returns 1: 42
    //       example 2: Atoi('-123')[0]
    //       returns 2: -123
    //       example 3: Atoi('abc')[0]
    //       returns 3: 0
    const normalized = String(s).trim();
    if (!/^-?\d+$/.test(normalized)) {
        return [0, new Error('strconv.Atoi: parsing "' + normalized + '": invalid syntax')];
    }
    const result = parseInt(normalized, 10);
    if (isNaN(result)) {
        return [0, new Error('strconv.Atoi: parsing "' + normalized + '": invalid syntax')];
    }
    return [result, null];
}