diff --git a/lib/Chunk.js b/lib/Chunk.js
index b7811c5b5..13dd33954 100644
--- a/lib/Chunk.js
+++ b/lib/Chunk.js
@@ -517,7 +517,7 @@ class Chunk {
 	 * @param {Object} options the size display options
 	 * @returns {number} the chunk size
 	 */
-	size(options) {
+	size(options = {}) {
 		return this.addMultiplierAndOverhead(this.modulesSize(), options);
 	}