StringUtils.cs

    /// <summary>
    /// Checks whether string is null, empty or consists of whitespace chars.
    /// </summary>
    public static bool IsNullEmptyOrWhiteSpace (string content)
    {
        if (String.IsNullOrEmpty(content))
            return true;

        return String.IsNullOrEmpty(content.TrimFull());
    }

    /// <summary>
    /// Performes <see cref="string.Trim"/> additionally removing any BOM and other service symbols.
    /// </summary>
    public static string TrimFull (this string source)
    {
        #if UNITY_WEBGL // WebGL build under .NET 4.6 fails when using Trim with UTF-8 chars. (should be fixed in Unity 2018.1)
        var whitespaceChars = new List<char> {
            '\u0009','\u000A','\u000B','\u000C','\u000D','\u0020','\u0085','\u00A0',
            '\u1680','\u2000','\u2001','\u2002','\u2003','\u2004','\u2005','\u2006',
            '\u2007','\u2008','\u2009','\u200A','\u2028','\u2029','\u202F','\u205F',
            '\u3000','\uFEFF','\u200B',
        };

        // Trim start.
        if (string.IsNullOrEmpty(source)) return source;
        var c = source[0];
        while (whitespaceChars.Contains(c))
        {
            if (source.Length <= 1) return string.Empty;
            source = source.Substring(1);
            c = source[0];
        }

        // Trim end.
        if (string.IsNullOrEmpty(source)) return source;
        c = source[source.Length - 1];
        while (whitespaceChars.Contains(c))
        {
            if (source.Length <= 1) return string.Empty;
            source = source.Substring(0, source.Length - 1);
            c = source[source.Length - 1];
        }

        return source;
        #else
        return source.Trim().Trim(new char[] { '\uFEFF', '\u200B' });
        #endif
    }