diff --git a/htmlhint-server/src/server.ts b/htmlhint-server/src/server.ts
index 02d34f6..345e24c 100644
--- a/htmlhint-server/src/server.ts
+++ b/htmlhint-server/src/server.ts
@@ -1965,6 +1965,102 @@ function createAttrNoDuplicationFix(
};
}
+/**
+ * Create auto-fix action for attr-value-no-duplication rule
+ * Removes duplicate values within attribute values (e.g., class="btn btn primary" -> class="btn primary")
+ */
+function createAttrValueNoDuplicationFix(
+ document: TextDocument,
+ diagnostic: Diagnostic,
+): CodeAction | null {
+ trace(
+ `[DEBUG] createAttrValueNoDuplicationFix called with diagnostic: ${JSON.stringify(diagnostic)}`,
+ );
+
+ if (!diagnostic.data || diagnostic.data.ruleId !== "attr-value-no-duplication") {
+ trace(
+ `[DEBUG] createAttrValueNoDuplicationFix: Invalid diagnostic data or ruleId`,
+ );
+ return null;
+ }
+
+ const text = document.getText();
+ const diagnosticOffset = document.offsetAt(diagnostic.range.start);
+
+ // Use robust tag boundary detection
+ const tagBoundaries = findTagBoundaries(text, diagnosticOffset);
+ if (!tagBoundaries) {
+ trace(`[DEBUG] createAttrValueNoDuplicationFix: Could not find tag boundaries`);
+ return null;
+ }
+
+ const { tagStart, tagEnd } = tagBoundaries;
+ const tagContent = text.substring(tagStart, tagEnd + 1);
+ trace(`[DEBUG] createAttrValueNoDuplicationFix: Found tag: ${tagContent}`);
+
+ // Parse attributes from the tag to find the one with duplicate values
+ const attrPattern = /(\w+(?:-\w+)*)\s*=\s*(?:"([^"]*)"|'([^']*)'|([^\s>]+))/g;
+ let match;
+ const edits: TextEdit[] = [];
+
+ while ((match = attrPattern.exec(tagContent)) !== null) {
+ const attrName = match[1];
+ const attrValue = match[2] || match[3] || match[4] || "";
+ const fullMatch = match[0];
+ const attrStartIndex = match.index;
+ const attrEndIndex = match.index + fullMatch.length;
+
+ // Check if this attribute contains duplicate values
+ if (attrValue.trim()) {
+ const values = attrValue.trim().split(/\s+/);
+ const uniqueValues = [...new Set(values)]; // Remove duplicates while preserving order
+
+ if (values.length !== uniqueValues.length) {
+ // Found duplicates, create an edit to fix them
+ const newAttrValue = uniqueValues.join(' ');
+ const quote = match[2] !== undefined ? '"' : match[3] !== undefined ? "'" : '';
+ const newFullMatch = quote
+ ? `${attrName}=${quote}${newAttrValue}${quote}`
+ : `${attrName}=${newAttrValue}`;
+
+ const absoluteStart = tagStart + attrStartIndex;
+ const absoluteEnd = tagStart + attrEndIndex;
+
+ edits.push({
+ range: {
+ start: document.positionAt(absoluteStart),
+ end: document.positionAt(absoluteEnd),
+ },
+ newText: newFullMatch,
+ });
+
+ trace(
+ `[DEBUG] createAttrValueNoDuplicationFix: Will replace "${fullMatch}" with "${newFullMatch}"`,
+ );
+ break; // Only fix one attribute per diagnostic
+ }
+ }
+ }
+
+ if (edits.length === 0) {
+ trace(`[DEBUG] createAttrValueNoDuplicationFix: No edits created`);
+ return null;
+ }
+
+ const workspaceEdit: WorkspaceEdit = {
+ changes: {
+ [document.uri]: edits,
+ },
+ };
+
+ return {
+ title: "Remove duplicate values from attribute",
+ kind: CodeActionKind.QuickFix,
+ edit: workspaceEdit,
+ isPreferred: true,
+ };
+}
+
/**
* Create auto-fix action for form-method-require rule
*/
@@ -2162,6 +2258,10 @@ async function createAutoFixes(
trace(`[DEBUG] Calling createAttrNoDuplicationFix`);
fix = createAttrNoDuplicationFix(document, diagnostic);
break;
+ case "attr-value-no-duplication":
+ trace(`[DEBUG] Calling createAttrValueNoDuplicationFix`);
+ fix = createAttrValueNoDuplicationFix(document, diagnostic);
+ break;
case "form-method-require":
trace(`[DEBUG] Calling createFormMethodRequireFix`);
fix = createFormMethodRequireFix(document, diagnostic);
diff --git a/htmlhint/CHANGELOG.md b/htmlhint/CHANGELOG.md
index 1268611..22c7a77 100644
--- a/htmlhint/CHANGELOG.md
+++ b/htmlhint/CHANGELOG.md
@@ -5,6 +5,7 @@ All notable changes to the "vscode-htmlhint" extension will be documented in thi
### v1.14.0 (2025-11-26)
- Add autofix for the `attr-no-duplication` rule
+- Add autofix for the `attr-value-no-duplication` rule
- Add autofix for the `form-method-require` rule
### v1.13.0 (2025-11-25)
diff --git a/htmlhint/README.md b/htmlhint/README.md
index d9b5c03..6975576 100644
--- a/htmlhint/README.md
+++ b/htmlhint/README.md
@@ -31,6 +31,7 @@ The extension provides automatic fixes for many common HTML issues. Currently su
- **`attr-no-duplication`** - Removes duplicate attributes (only when values are identical)
- **`attr-no-unnecessary-whitespace`** - Removes unnecessary whitespace around attributes
- **`attr-value-double-quotes`** - Converts single quotes to double quotes in attributes
+- **`attr-value-no-duplication`** - Removes duplicate values within attributes (e.g., `class="btn btn primary"` → `class="btn primary"`)
- **`attr-whitespace`** - Removes leading and trailing whitespace from attribute values
- **`button-type-require`** - Adds type attribute to buttons
- **`doctype-first`** - Adds DOCTYPE declaration at the beginning
diff --git a/test/autofix/.htmlhintrc b/test/autofix/.htmlhintrc
index 5e3a8e2..e2b0c0e 100644
--- a/test/autofix/.htmlhintrc
+++ b/test/autofix/.htmlhintrc
@@ -1,6 +1,7 @@
{
"alt-require": true,
"attr-lowercase": true,
+ "attr-no-duplication": true,
"attr-no-unnecessary-whitespace": true,
"attr-value-double-quotes": true,
"attr-value-no-duplication": true,
diff --git a/test/autofix/alt-test.html b/test/autofix/alt-test.html
index 8dd4787..987b34c 100644
--- a/test/autofix/alt-test.html
+++ b/test/autofix/alt-test.html
@@ -1,6 +1,8 @@
-
+
+
+
Alt Attribute Test
diff --git a/test/autofix/attr-no-duplication-test.html b/test/autofix/attr-no-duplication-test.html
new file mode 100644
index 0000000..0a6d67c
--- /dev/null
+++ b/test/autofix/attr-no-duplication-test.html
@@ -0,0 +1,33 @@
+
+
+
+
+
+ Attribute No Duplication Test
+
+
+
+ Button 1
+
+
+ Button 2
+
+
+ Button 3
+
+
+ Button 4
+
+
+ Button 5
+
+
+ Button 6
+
+
+
+
+
+ Button 8
+
+
diff --git a/test/autofix/attr-value-no-duplication-test.html b/test/autofix/attr-value-no-duplication-test.html
new file mode 100644
index 0000000..3bee64c
--- /dev/null
+++ b/test/autofix/attr-value-no-duplication-test.html
@@ -0,0 +1,33 @@
+
+
+
+
+
+ Attribute Value No Duplication Test
+
+
+
+ Button 1
+
+
+ Button 2
+
+
+ Button 3
+
+
+ Button 4
+
+
+ Button 5
+
+
+ Button 6
+
+
+ Button 7
+
+
+ Button 8
+
+
diff --git a/test/autofix/button-test.html b/test/autofix/button-test.html
index 5ef8316..f2bcb53 100644
--- a/test/autofix/button-test.html
+++ b/test/autofix/button-test.html
@@ -1,8 +1,8 @@
-
-
+
+
Button Type Test
diff --git a/test/autofix/meta-description-test.html b/test/autofix/meta-description-test.html
index 6fab150..682f1eb 100644
--- a/test/autofix/meta-description-test.html
+++ b/test/autofix/meta-description-test.html
@@ -2,8 +2,8 @@
-
-
+
+
Meta Description Test