The link rel attribute should be handled as a token list to allow mixing manual link decorators for the same attribute

packages/ckeditor5-engine/src/conversion/downcasthelpers.ts

@@ -1664,60 +1664,35 @@ function changeAttribute( attributeCreator: AttributeCreatorFunction ) {
 
 		// First remove the old attribute if there was one.
 		if ( data.attributeOldValue !== null && oldAttribute ) {
-			if ( oldAttribute.key == 'class' ) {
-				const classes = typeof oldAttribute.value == 'string' ? oldAttribute.value.split( /\s+/ ) : oldAttribute.value;
+			let value = oldAttribute.value;
 
-				for ( const className of classes ) {
-					viewWriter.removeClass( className, viewElement );
-				}
-			} else if ( oldAttribute.key == 'style' ) {
+			if ( oldAttribute.key == 'style' ) {
 				if ( typeof oldAttribute.value == 'string' ) {
-					const styles = new StylesMap( viewWriter.document.stylesProcessor );
-
-					styles.setTo( oldAttribute.value );
-
-					for ( const [ key ] of styles.getStylesEntries() ) {
-						viewWriter.removeStyle( key, viewElement );
-					}
+					value = new StylesMap( viewWriter.document.stylesProcessor )
+						.setTo( oldAttribute.value )
+						.getStylesEntries()
+						.map( ( [ key ] ) => key );
 				} else {
-					const keys = Object.keys( oldAttribute.value );
-
-					for ( const key of keys ) {
-						viewWriter.removeStyle( key, viewElement );
-					}
+					value = Object.keys( oldAttribute.value );
 				}
-			} else {
-				viewWriter.removeAttribute( oldAttribute.key, viewElement );
 			}
+
+			viewWriter.removeAttribute( oldAttribute.key, value as ArrayOrItem<string>, viewElement );
 		}
 
 		// Then set the new attribute.
 		if ( data.attributeNewValue !== null && newAttribute ) {
-			if ( newAttribute.key == 'class' ) {
-				const classes = typeof newAttribute.value == 'string' ? newAttribute.value.split( /\s+/ ) : newAttribute.value;
-
-				for ( const className of classes ) {
-					viewWriter.addClass( className, viewElement );
-				}
-			} else if ( newAttribute.key == 'style' ) {
-				if ( typeof newAttribute.value == 'string' ) {
-					const styles = new StylesMap( viewWriter.document.stylesProcessor );
-
-					styles.setTo( newAttribute.value );
-
-					for ( const [ key, value ] of styles.getStylesEntries() ) {
-						viewWriter.setStyle( key, value, viewElement );
-					}
-				} else {
-					const keys = Object.keys( newAttribute.value );
-
-					for ( const key of keys ) {
-						viewWriter.setStyle( key, ( newAttribute.value as Record<string, string> )[ key ], viewElement );
-					}
-				}
-			} else {
-				viewWriter.setAttribute( newAttribute.key, newAttribute.value as string, viewElement );
+			let value = newAttribute.value;
+
+			if ( newAttribute.key == 'style' && typeof newAttribute.value == 'string' ) {
+				value = Object.fromEntries(
+					new StylesMap( viewWriter.document.stylesProcessor )
+						.setTo( newAttribute.value )
+						.getStylesEntries()
+				);
 			}
+
+			viewWriter.setAttribute( newAttribute.key, value, false, viewElement );
 		}
 	};
 }