[TypeScript] powerMod implementation

powerMod.ts

// x^p mod m
function powerMod(x: number, p: number, m: number): number {
    if (m === 1) {
        return 0;
    }
    x = x % m;

    let result = 1;
    while (p > 0) {
        if (p % 2 === 1) {
            result = (result * x) % m;
        }
        x = (x * x) % m;
        p = p >> 1;
    }

    return result;
}

function powerModBigInt(x: bigint, p: bigint, m: bigint): bigint {
    if (m === BigInt(1)) {
        return BigInt(0);
    }
    x = x % m;

    let result = BigInt(1);
    while (p > 0) {
        if (p % BigInt(2) === BigInt(1)) {
            result = (result * x) % m;
        }
        x = (x * x) % m;
        p = p >> BigInt(1);
    }

    return result;
}