function _synthesizeIPv6Addresses0()

in react/features/mobile/polyfills/ipv6utils.js [75:153]
67 lines of code
17 McCabe index (conditional complexity)

function _synthesizeIPv6Addresses0(sessionDescription) {
    const sdp = sessionDescription.sdp;
    let start = 0;
    const lines = [];
    const ips = new Map();

    do {
        const end = sdp.indexOf('\r\n', start);
        let line;

        if (end === -1) {
            line = sdp.substring(start);

            // Break out of the loop at the end of the iteration.
            start = undefined;
        } else {
            line = sdp.substring(start, end);
            start = end + 2;
        }

        if (line.startsWith('a=candidate:')) {
            const candidate = line.split(' ');

            if (candidate.length >= 10 && candidate[6] === 'typ') {
                const ip4s = [ candidate[4] ];
                let abort = false;

                for (let i = 8; i < candidate.length; ++i) {
                    if (candidate[i] === 'raddr') {
                        ip4s.push(candidate[++i]);
                        break;
                    }
                }

                for (const ip of ip4s) {
                    if (ip.indexOf(':') === -1) {
                        ips.has(ip)
                            || ips.set(ip, new Promise((resolve, reject) => {
                                const v = ips.get(ip);

                                if (v && typeof v === 'string') {
                                    resolve(v);
                                } else {
                                    _synthesizeIPv6FromIPv4Address(ip).then(
                                        value => {
                                            if (!value
                                                    || value.indexOf(':') === -1
                                                    || value === ips.get(ip)) {
                                                ips.delete(ip);
                                            } else {
                                                ips.set(ip, value);
                                            }
                                            resolve(value);
                                        },
                                        reject);
                                }
                            }));
                    } else {
                        abort = true;
                        break;
                    }
                }
                if (abort) {
                    ips.clear();
                    break;
                }

                line = candidate;
            }
        }

        lines.push(line);
    } while (start);

    return {
        ips,
        lines
    };
}