Allow redundant hyphens

README.md

@@ -127,6 +127,17 @@ function yasglobal_allow_uppercaps() {
 add_filter( 'custom_permalinks_allow_caps', 'yasglobal_allow_uppercaps' );
 ```
 
+### Allow Redundant Hyphens
+
+To allow redundant hyphens, please add below-mentioned line in your theme `functions.php`:
+
+```php
+function yasglobal_redundant_hyphens() {
+  return true;
+}
+add_filter( 'custom_permalinks_redundant_hyphens', 'yasglobal_redundant_hyphens' );
+```
+
 ### Manipulate Permalink Before Saving
 
 To make changes in permalink before saving, please use `custom_permalink_before_saving` filter. Here is an example to see how it works.

includes/class-custom-permalinks-form.php

@@ -337,7 +337,16 @@ private function sanitize_permalink( $permalink, $language_code ) {
 		$permalink = preg_replace( '|-+|', '-', $permalink );
 		$permalink = str_replace( '-/', '/', $permalink );
 		$permalink = str_replace( '/-', '/', $permalink );
-		$permalink = trim( $permalink, '-' );
+
+		/*
+		 * Avoid trimming hyphens if filter returns `false`.
+		 *
+		 * @since 2.4.0
+		 */
+		$trim_hyphen = apply_filters( 'custom_permalinks_redundant_hyphens', false );
+		if ( ! is_bool( $trim_hyphen ) || ! $trim_hyphen ) {
+			$permalink = trim( $permalink, '-' );
+		}
 
 		return $permalink;
 	}