fix memory leak

bodasia · web-flow · commit b72a6b188957 · 2019-10-29T17:06:56.000+02:00
For many reasons, node caches and leaves in memory (for pretty lengthy amount of time) HTTPRequest instances. Form-data doesn't unsubscribe from 'error' and 'response' event, leaving references to finish / callback. This is kind-of okay in most cases (HTTPRequest's do die after a while), it might be a problem with large payloads or other memory-hungry situations.
This was only tested with NodeJS 8 - future versions might change how they are working with HTTPRequest's objects.
diff --git a/lib/form_data.js b/lib/form_data.js
@@ -462,8 +462,17 @@ FormData.prototype.submit = function(params, cb) {
 
     this.pipe(request);
     if (cb) {
-      request.on('error', cb);
-      request.on('response', cb.bind(this, null));
+      function callback(err, res) {
+        request.removeListener('error', callback);
+        request.removeListener('response', onResponse);
+
+        return cb.call(this, err, res);
+      }
+
+      const onResponse = callback.bind(this, null);
+
+      request.on('error', callback);
+      request.on('response', onResponse);
     }
   }.bind(this));
 
