diff --git a/lib/web/fetch/data-url.js b/lib/web/fetch/data-url.js
index 2996feca92a..c77747fc0d7 100644
--- a/lib/web/fetch/data-url.js
+++ b/lib/web/fetch/data-url.js
@@ -471,9 +471,9 @@ function forgivingBase64 (data) {
 /**
  * @param {string} input
  * @param {{ position: number }} position
- * @param {boolean?} extractValue
+ * @param {boolean} [extractValue=false]
  */
-function collectAnHTTPQuotedString (input, position, extractValue) {
+function collectAnHTTPQuotedString (input, position, extractValue = false) {
   // 1. Let positionStart be position.
   const positionStart = position.position