Function letterEncode

TestFlight/TestFlightAccount.js:280–293

(e)

// private encode method, based on variant in RFC4648
function letterEncode(e) {
    e = e.split("").map(e => e.charCodeAt());
    const t = new Uint8Array(4 * Math.ceil(8 * e.length / 4));
    let n = 0;
    for (const o of e) {
        let e = 128;
        for (let r = 0; r < 8; r++) t[n++] = o & e ? 1 : 0, e >>= 1
    }
    let o = "",
        r = 0;
    return t.forEach((e, t) => {
        r = r << 1 | e, (t + 1) % 4 == 0 && (o += "XKNWSPRMCTGZVDHF"[r], r = 0)
    }), o
}

function letterDecode(e) {
    const t = new Uint8Array(4 * e.length);