add toCssSize

src/utils/Toolkit.ts

@@ -327,4 +327,11 @@ export default class Toolkit {
 			func(arg);
 		}
 	}
+
+	public static toCssSize(value: number | string): string {
+		if (typeof value === "number") {
+			return `${value}px`;
+		}
+		return value;
+	};
 }