locutus/esm/golang/subtle/ConstantTimeEq.js

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

export function ConstantTimeEq(x, y) {
    //      discuss at: https://locutus.io/golang/ConstantTimeEq
    // parity verified: Go 1.23
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Mirrors Go subtle.ConstantTimeEq bitwise semantics on 32-bit integer values.
    //       example 1: ConstantTimeEq(42, 42)
    //       returns 1: 1
    //       example 2: ConstantTimeEq(42, 7)
    //       returns 2: 0
    //       example 3: ConstantTimeEq(-1, -1)
    //       returns 3: 1
    const left = x | 0;
    const right = y | 0;
    const diff = left ^ right;
    const sign = (diff | -diff) >>> 31;
    return sign ^ 1;
}