Truncate String Without Word Break

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1/// <summary>
2/// Truncate string at a word near to the limit specified. Avoid word split.
3/// </summary>
4/// <param name="input">string</param>
5/// <param name="length"></param>
6/// <param name="appendDots"></param>
7/// <returns></returns>
8public static string TruncateAtWord(this string input, int length, bool appendDots = false)
9{
10    if (input == null || input.Length < length)
11        return input;
12    var iNextSpace = input.LastIndexOf(" ", length, StringComparison.Ordinal);
13    var trimmedInput = string.Format("{0}", input.Substring(0, (iNextSpace > 0) ? iNextSpace : length).Trim());
14
15    if (appendDots)
16    {
17        return trimmedInput + "...";
18    }
19    return trimmedInput;
20}

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1[Fact]
2public void TruncateAtWordTests()
3{
4    "This is a long sentence".TruncateAtWord(6).Should().Be("This");
5    "This is a long sentence".TruncateAtWord(7).Should().Be("This is");
6}