Updated the files.

my-app/node_modules/webpack-dev-server/client/utils/getCurrentScriptSource.js

@@ -0,0 +1,24 @@
+/**
+ * @returns {string}
+ */
+function getCurrentScriptSource() {
+  // `document.currentScript` is the most accurate way to find the current script,
+  // but is not supported in all browsers.
+  if (document.currentScript) {
+    return document.currentScript.getAttribute("src");
+  }
+
+  // Fallback to getting all scripts running in the document.
+  var scriptElements = document.scripts || [];
+  var scriptElementsWithSrc = Array.prototype.filter.call(scriptElements, function (element) {
+    return element.getAttribute("src");
+  });
+  if (scriptElementsWithSrc.length > 0) {
+    var currentScript = scriptElementsWithSrc[scriptElementsWithSrc.length - 1];
+    return currentScript.getAttribute("src");
+  }
+
+  // Fail as there was no script to use.
+  throw new Error("[webpack-dev-server] Failed to get current script source.");
+}
+export default getCurrentScriptSource;