Support for trimming chars from generated slug's start/end.

README.md

@@ -214,4 +214,37 @@ Specifying the `DeniedCharactersRegex` option will disable the character removal
 
 This will limit the length of the generated slug to be a maximum of the number of chars given by the parameter. If the truncation happens in a way that a trailing `-` is left, it will be removed.
 
-- Default value: `null`
+- Default value: `null`
+
+### `TrimChars`, `TrimEndChars`, `TrimStartChars`
+
+Trim options to remove characters from the input before replacements and character filtering. This is useful to prevent generated slug to start/end with certain characters like dot.
+
+- Options
+  - `TrimChars` — characters to trim from both ends (behaves like `string.Trim(char[])`).
+  - `TrimEndChars` — characters to trim from the end (behaves like `string.TrimEnd(char[])`).
+  - `TrimStartChars` — characters to trim from the start (behaves like `string.TrimStart(char[])`).
+
+- Default value: all three are empty arrays (no extra trimming).
+
+- Example:
+
+```csharp
+var helper = new SlugHelper(new SlugHelperConfiguration
+{
+    TrimChars = ['.']
+});
+Console.WriteLine(helper.GenerateSlug(".hello world.")); // "hello-world"
+
+helper = new SlugHelper(new SlugHelperConfiguration
+{
+    TrimEndChars = ['.']
+});
+Console.WriteLine(helper.GenerateSlug(".hello world.")); // ".hello-world"
+
+helper = new SlugHelper(new SlugHelperConfiguration
+{
+    TrimStartChars = ['.']
+});
+Console.WriteLine(helper.GenerateSlug(".hello world.")); // "hello-world."
+```

src/Slugify.Core/SlugHelper.cs

@@ -38,6 +38,9 @@ public virtual string GenerateSlug(string inputString)
         normalizedInput = normalizedInput.Normalize(NormalizationForm.FormD);
         normalizedInput = Config.TrimWhitespace ? normalizedInput.Trim() : normalizedInput;
         normalizedInput = Config.ForceLowerCase ? normalizedInput.ToLowerInvariant() : normalizedInput;
+        normalizedInput = Config.TrimChars.Length != 0 ? normalizedInput.Trim(Config.TrimChars) : normalizedInput;
+        normalizedInput = Config.TrimEndChars.Length != 0 ? normalizedInput.TrimEnd(Config.TrimEndChars) : normalizedInput;
+        normalizedInput = Config.TrimStartChars.Length != 0 ? normalizedInput.TrimStart(Config.TrimStartChars) : normalizedInput;
 
         var sb = new StringBuilder(normalizedInput);
 

src/Slugify.Core/SlugHelperConfiguration.cs

@@ -61,6 +61,21 @@ public class SlugHelperConfiguration
     /// </summary>
     public bool TrimWhitespace { get; set; } = true;
 
+    /// <summary>
+    /// List of characters to be trimmed (removed from both ends) from generated slug
+    /// </summary>
+    public char[] TrimChars { get; set; } = [];
+
+    /// <summary>
+    /// List of characters to be trimmed from end of the generated slug
+    /// </summary>
+    public char[] TrimEndChars { get; set; } = [];
+
+    /// <summary>
+    /// List of characters to be trimmed from start of the generated slug
+    /// </summary>
+    public char[] TrimStartChars { get; set; } = [];
+
     /// <summary>
     /// Represents the maximum length of the slug. If the slug is longer than this value, it will be truncated.
     /// </summary>

tests/Slugify.Core.Tests/SlugHelperTests.cs

@@ -512,6 +512,51 @@ public void TestNoTrimmingWithLeadingAndTrailingSpaces(ISlugHelper helper)
         Assert.Equal(expected, helper.GenerateSlug(original));
     }
 
+    [Theory]
+    [MemberData(nameof(GenerateStandardSluggers))]
+    public void TestTrimmingEndChars(ISlugHelper helper)
+    {
+        const string original = "hello._world._";
+        const string expected = "hello._world";
+
+        helper.Config = new SlugHelperConfiguration
+        {
+            TrimEndChars = [ '.', '_' ],
+        };
+
+        Assert.Equal(expected, helper.GenerateSlug(original));
+    }
+
+    [Theory]
+    [MemberData(nameof(GenerateStandardSluggers))]
+    public void TestTrimmingStartChars(ISlugHelper helper)
+    {
+        const string original = "._hello._world";
+        const string expected = "hello._world";
+
+        helper.Config = new SlugHelperConfiguration
+        {
+            TrimStartChars = [ '.', '_' ],
+        };
+
+        Assert.Equal(expected, helper.GenerateSlug(original));
+    }
+
+    [Theory]
+    [MemberData(nameof(GenerateStandardSluggers))]
+    public void TestTrimmingChars(ISlugHelper helper)
+    {
+        const string original = "._hello._world._";
+        const string expected = "hello._world";
+
+        helper.Config = new SlugHelperConfiguration
+        {
+            TrimChars = [ '.', '_' ],
+        };
+
+        Assert.Equal(expected, helper.GenerateSlug(original));
+    }
+
     [Theory]
     [MemberData(nameof(GenerateStandardSluggers))]
     public void TestReplacementWithEmptyStringThenCollapsing(ISlugHelper helper)