function detectDesktopOS()

in tools/CCPConnectivityTestTools/scripts/detectRTC.js [347:472]
120 lines of code
11 McCabe index (conditional complexity)

    function detectDesktopOS() {
        var unknown = '-';

        var nVer = navigator.appVersion;
        var nAgt = navigator.userAgent;

        var os = unknown;
        var clientStrings = [{
            s: 'Windows 10',
            r: /(Windows 10.0|Windows NT 10.0)/
        }, {
            s: 'Windows 8.1',
            r: /(Windows 8.1|Windows NT 6.3)/
        }, {
            s: 'Windows 8',
            r: /(Windows 8|Windows NT 6.2)/
        }, {
            s: 'Windows 7',
            r: /(Windows 7|Windows NT 6.1)/
        }, {
            s: 'Windows Vista',
            r: /Windows NT 6.0/
        }, {
            s: 'Windows Server 2003',
            r: /Windows NT 5.2/
        }, {
            s: 'Windows XP',
            r: /(Windows NT 5.1|Windows XP)/
        }, {
            s: 'Windows 2000',
            r: /(Windows NT 5.0|Windows 2000)/
        }, {
            s: 'Windows ME',
            r: /(Win 9x 4.90|Windows ME)/
        }, {
            s: 'Windows 98',
            r: /(Windows 98|Win98)/
        }, {
            s: 'Windows 95',
            r: /(Windows 95|Win95|Windows_95)/
        }, {
            s: 'Windows NT 4.0',
            r: /(Windows NT 4.0|WinNT4.0|WinNT|Windows NT)/
        }, {
            s: 'Windows CE',
            r: /Windows CE/
        }, {
            s: 'Windows 3.11',
            r: /Win16/
        }, {
            s: 'Android',
            r: /Android/
        }, {
            s: 'Open BSD',
            r: /OpenBSD/
        }, {
            s: 'Sun OS',
            r: /SunOS/
        }, {
            s: 'Linux',
            r: /(Linux|X11)/
        }, {
            s: 'iOS',
            r: /(iPhone|iPad|iPod)/
        }, {
            s: 'Mac OS X',
            r: /Mac OS X/
        }, {
            s: 'Mac OS',
            r: /(MacPPC|MacIntel|Mac_PowerPC|Macintosh)/
        }, {
            s: 'QNX',
            r: /QNX/
        }, {
            s: 'UNIX',
            r: /UNIX/
        }, {
            s: 'BeOS',
            r: /BeOS/
        }, {
            s: 'OS/2',
            r: /OS\/2/
        }, {
            s: 'Search Bot',
            r: /(nuhk|Googlebot|Yammybot|Openbot|Slurp|MSNBot|Ask Jeeves\/Teoma|ia_archiver)/
        }];
        for (var i = 0, cs; cs = clientStrings[i]; i++) {
            if (cs.r.test(nAgt)) {
                os = cs.s;
                break;
            }
        }

        var osVersion = unknown;

        if (/Windows/.test(os)) {
            if (/Windows (.*)/.test(os)) {
                osVersion = /Windows (.*)/.exec(os)[1];
            }
            os = 'Windows';
        }

        switch (os) {
            case 'Mac OS X':
                if (/Mac OS X (10[\.\_\d]+)/.test(nAgt)) {
                    osVersion = /Mac OS X (10[\.\_\d]+)/.exec(nAgt)[1];
                }
                break;
            case 'Android':
                if (/Android ([\.\_\d]+)/.test(nAgt)) {
                    osVersion = /Android ([\.\_\d]+)/.exec(nAgt)[1];
                }
                break;
            case 'iOS':
                if (/OS (\d+)_(\d+)_?(\d+)?/.test(nAgt)) {
                    osVersion = /OS (\d+)_(\d+)_?(\d+)?/.exec(nVer);
                    osVersion = osVersion[1] + '.' + osVersion[2] + '.' + (osVersion[3] | 0);
                }
                break;
        }

        return {
            osName: os,
            osVersion: osVersion
        };
    }