Update README.md

Update utils.ts - change type to StyleValue

packages/style-engine/README.md

@@ -270,11 +270,11 @@ Example:
 
 _Parameters_
 
--   _styleValue_ `CSSStyleValue`: A raw style value.
+-   _styleValue_ `StyleValue`: A string representing a raw CSS value. Non-strings won't be processed.
 
 _Returns_
 
--   `CSSStyleValue`: A CSS var value.
+-   `StyleValue`: A CSS custom var value if the incoming style value is a preset value.
 
 <!-- END TOKEN(Autogenerated API docs) -->
 

packages/style-engine/src/styles/utils.ts

@@ -136,14 +136,14 @@ export function generateBoxRules(
  *
  * `getCSSValueFromRawStyle( 'var:preset|color|heavenlyBlue' )` // returns 'var(--wp--preset--color--heavenly-blue)'
  *
- * @param styleValue A raw style value.
+ * @param styleValue A string representing a raw CSS value. Non-strings won't be processed.
  *
- * @return A CSS var value.
+ * @return A CSS custom var value if the incoming style value is a preset value.
  */
 
-export function getCSSValueFromRawStyle< CSSStyleValue = string >(
-	styleValue: CSSStyleValue
-): CSSStyleValue {
+export function getCSSValueFromRawStyle< StyleValue = string >(
+	styleValue: StyleValue
+): StyleValue {
 	if (
 		typeof styleValue === 'string' &&
 		styleValue.startsWith( VARIABLE_REFERENCE_PREFIX )
@@ -162,7 +162,7 @@ export function getCSSValueFromRawStyle< CSSStyleValue = string >(
 				} )
 			)
 			.join( VARIABLE_PATH_SEPARATOR_TOKEN_STYLE );
-		return `var(--wp--${ variable })` as CSSStyleValue;
+		return `var(--wp--${ variable })` as StyleValue;
 	}
 	return styleValue;
 }