locutus/esm/golang/subtle/ConstantTimeCompare.js

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

const textEncoder = new TextEncoder();
export function ConstantTimeCompare(x, y) {
    //      discuss at: https://locutus.io/golang/subtle/ConstantTimeCompare
    // parity verified: Go 1.23
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Compares UTF-8 byte sequences in constant time.
    //       example 1: ConstantTimeCompare('hunter2', 'hunter2')
    //       returns 1: 1
    //       example 2: ConstantTimeCompare('hunter2', 'hunter3')
    //       returns 2: 0
    //       example 3: ConstantTimeCompare('hunter2', 'hunt')
    //       returns 3: 0
    const left = textEncoder.encode(String(x));
    const right = textEncoder.encode(String(y));
    if (left.length !== right.length) {
        return 0;
    }
    let diff = 0;
    for (let i = 0; i < left.length; i += 1) {
        diff |= (left[i] ?? 0) ^ (right[i] ?? 0);
    }
    return diff === 0 ? 1 : 0;
}