[Fix] set Symbol.toStringTag in the proper place

ljharb · ljharb · commit 76d0dee43933 · 2025-11-17T12:45:49.000+09:00
See #396 (comment)
diff --git a/lib/form_data.js b/lib/form_data.js
@@ -488,7 +488,7 @@ FormData.prototype._error = function (err) {
 FormData.prototype.toString = function () {
   return '[object FormData]';
 };
-setToStringTag(FormData, 'FormData');
+setToStringTag(FormData.prototype, 'FormData');
 
 // Public API
 module.exports = FormData;
diff --git a/test/integration/test-to-string.js b/test/integration/test-to-string.js
@@ -5,3 +5,4 @@ var assert = common.assert;
 var FormData = require(common.dir.lib + '/form_data');
 
 assert(String(new FormData()) === '[object FormData]');
+assert(Object.prototype.toString.call(new FormData()) === '[object FormData]');

Original file line number	Diff line number	Diff line change
`@@ -5,3 +5,4 @@ var assert = common.assert;`
`5`	`5`	`var FormData = require(common.dir.lib + '/form_data');`
`6`	`6`
`7`	`7`	`assert(String(new FormData()) === '[object FormData]');`
	`8`	`+assert(Object.prototype.toString.call(new FormData()) === '[object FormData]');`