fixed issue #157

lib/single-file/util/doc-util.js

@@ -94,7 +94,13 @@ this.docUtil = this.docUtil || (() => {
 					const reader = new FileReader();
 					reader.readAsText(blob.slice(0, maxSize));
 					return await new Promise((resolve, reject) => {
-						reader.addEventListener("load", () => resolve(reader.result), false);
+						reader.addEventListener("load", () => {
+							if (content.startsWith(reader.result)) {
+								resolve(reader.result);
+							} else {
+								this.truncateContent(content, maxSize - 1).then(resolve).catch(reject);
+							}
+						}, false);
 						reader.addEventListener("error", reject, false);
 					});
 				},