diff --git a/.gitignore b/.gitignore
index 5790d187..6d8a8023 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,8 @@ package-lock.json
 coverage/
 node_modules/
 test/tmp/
+
+# Only apps should have lockfiles
+npm-shrinkwrap.json
+package-lock.json
+yarn.lock
diff --git a/.npmrc b/.npmrc
new file mode 100644
index 00000000..43c97e71
--- /dev/null
+++ b/.npmrc
@@ -0,0 +1 @@
+package-lock=false
diff --git a/lib/form_data.js b/lib/form_data.js
index e05c8f1a..3479d18c 100644
--- a/lib/form_data.js
+++ b/lib/form_data.js
@@ -8,6 +8,7 @@ var fs = require('fs');
 var Stream = require('stream').Stream;
 var mime = require('mime-types');
 var asynckit = require('asynckit');
+var setToStringTag = require('es-set-tostringtag');
 var populate = require('./populate.js');
 
 // Public API
@@ -102,7 +103,7 @@ FormData.prototype._trackLength = function(header, value, options) {
     FormData.LINE_BREAK.length;
 
   // empty or either doesn't have path or not an http response or not a stream
-  if (!value || ( !value.path && !(value.readable && value.hasOwnProperty('httpVersion')) && !(value instanceof Stream))) {
+  if (!value || ( !value.path && !(value.readable && Object.prototype.hasOwnProperty.call(value, 'httpVersion')) && !(value instanceof Stream))) {
     return;
   }
 
@@ -113,8 +114,7 @@ FormData.prototype._trackLength = function(header, value, options) {
 };
 
 FormData.prototype._lengthRetriever = function(value, callback) {
-
-  if (value.hasOwnProperty('fd')) {
+  if (Object.prototype.hasOwnProperty.call(value, 'fd')) {
 
     // take read range into a account
     // `end` = Infinity –> read file till the end
@@ -149,11 +149,11 @@ FormData.prototype._lengthRetriever = function(value, callback) {
     }
 
   // or http response
-  } else if (value.hasOwnProperty('httpVersion')) {
+  } else if (Object.prototype.hasOwnProperty.call(value, 'httpVersion')) {
     callback(null, +value.headers['content-length']);
 
   // or request stream http://github.com/mikeal/request
-  } else if (value.hasOwnProperty('httpModule')) {
+  } else if (Object.prototype.hasOwnProperty.call(value, 'httpModule')) {
     // wait till response come back
     value.on('response', function(response) {
       value.pause();
@@ -193,22 +193,23 @@ FormData.prototype._multiPartHeader = function(field, value, options) {
 
   var header;
   for (var prop in headers) {
-    if (!headers.hasOwnProperty(prop)) continue;
-    header = headers[prop];
+    if (Object.prototype.hasOwnProperty.call(headers, prop)) {
+      header = headers[prop];
 
-    // skip nullish headers.
-    if (header == null) {
-      continue;
-    }
+      // skip nullish headers.
+      if (header == null) {
+        continue;
+      }
 
-    // convert all headers to arrays.
-    if (!Array.isArray(header)) {
-      header = [header];
-    }
+      // convert all headers to arrays.
+      if (!Array.isArray(header)) {
+        header = [header];
+      }
 
-    // add non-empty headers.
-    if (header.length) {
-      contents += prop + ': ' + header.join('; ') + FormData.LINE_BREAK;
+      // add non-empty headers.
+      if (header.length) {
+        contents += prop + ': ' + header.join('; ') + FormData.LINE_BREAK;
+      }
     }
   }
 
@@ -229,7 +230,7 @@ FormData.prototype._getContentDisposition = function(value, options) {
     // formidable and the browser add a name property
     // fs- and request- streams have path property
     filename = path.basename(options.filename || value.name || value.path);
-  } else if (value.readable && value.hasOwnProperty('httpVersion')) {
+  } else if (value.readable && Object.prototype.hasOwnProperty.call(value, 'httpVersion')) {
     // or try http response
     filename = path.basename(value.client._httpMessage.path || '');
   }
@@ -257,7 +258,7 @@ FormData.prototype._getContentType = function(value, options) {
   }
 
   // or if it's http-reponse
-  if (!contentType && value.readable && value.hasOwnProperty('httpVersion')) {
+  if (!contentType && value.readable && Object.prototype.hasOwnProperty.call(value, 'httpVersion')) {
     contentType = value.headers['content-type'];
   }
 
@@ -298,7 +299,7 @@ FormData.prototype.getHeaders = function(userHeaders) {
   };
 
   for (header in userHeaders) {
-    if (userHeaders.hasOwnProperty(header)) {
+    if (Object.prototype.hasOwnProperty.call(userHeaders, header)) {
       formHeaders[header.toLowerCase()] = userHeaders[header];
     }
   }
@@ -319,7 +320,7 @@ FormData.prototype.getBoundary = function() {
 };
 
 FormData.prototype.getBuffer = function() {
-  var dataBuffer = new Buffer.alloc( 0 );
+  var dataBuffer = new Buffer.alloc(0);
   var boundary = this.getBoundary();
 
   // Create the form content. Add Line breaks to the end of data.
@@ -499,3 +500,4 @@ FormData.prototype._error = function(err) {
 FormData.prototype.toString = function () {
   return '[object FormData]';
 };
+setToStringTag(FormData, 'FormData');
diff --git a/package.json b/package.json
index 9bd12c95..47fc92b7 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "author": "Felix Geisendörfer <felix@debuggable.com> (http://debuggable.com/)",
   "name": "form-data",
   "description": "A library to create readable \"multipart/form-data\" streams. Can be used to submit forms and file uploads to other web applications.",
-  "version": "4.0.1",
+  "version": "4.0.2",
   "repository": {
     "type": "git",
     "url": "git://github.com/form-data/form-data.git"
@@ -43,29 +43,32 @@
   "dependencies": {
     "asynckit": "^0.4.0",
     "combined-stream": "^1.0.8",
+    "es-set-tostringtag": "^2.1.0",
     "mime-types": "^2.1.12"
   },
   "devDependencies": {
-    "@types/node": "^12.0.10",
-    "browserify": "^13.1.1",
+    "@types/combined-stream": "^1.0.6",
+    "@types/mime-types": "^2.1.4",
+    "@types/node": "^12.20.55",
+    "browserify": "^13.3.0",
     "browserify-istanbul": "^2.0.0",
-    "coveralls": "^3.0.4",
-    "cross-spawn": "^6.0.5",
-    "eslint": "^6.0.1",
+    "coveralls": "^3.1.1",
+    "cross-spawn": "^6.0.6",
+    "eslint": "^6.8.0",
     "fake": "^0.2.2",
     "far": "^0.0.7",
-    "formidable": "^1.0.17",
-    "in-publish": "^2.0.0",
+    "formidable": "^1.2.6",
+    "in-publish": "^2.0.1",
     "is-node-modern": "^1.0.0",
     "istanbul": "^0.4.5",
     "obake": "^0.1.2",
-    "puppeteer": "^1.19.0",
-    "pkgfiles": "^2.3.0",
-    "pre-commit": "^1.1.3",
-    "request": "^2.88.0",
+    "pkgfiles": "^2.3.2",
+    "pre-commit": "^1.2.2",
+    "puppeteer": "^1.20.0",
+    "request": "~2.87.0",
     "rimraf": "^2.7.1",
-    "tape": "^4.6.2",
-    "typescript": "^3.5.2"
+    "tape": "^5.9.0",
+    "typescript": "^3.9.10"
   },
   "license": "MIT"
 }
diff --git a/test/common.js b/test/common.js
index 7da855c1..f3d63719 100644
--- a/test/common.js
+++ b/test/common.js
@@ -40,7 +40,7 @@ common.testFields = function (FIELDS, callback) {
     var incomingForm = new IncomingForm({uploadDir: common.dir.tmp});
 
     incomingForm.parse(req);
-    
+
     common.actions.checkForm(incomingForm, FIELDS, function (fieldsChecked) {
       // keep track of number of the processed fields
       callback(fieldsPassed - fieldsChecked);
@@ -55,18 +55,17 @@ common.testFields = function (FIELDS, callback) {
 common.actions = {};
 
 // generic form field population
-common.actions.populateFields = function(form, fields)
-{
+common.actions.populateFields = function (form, fields) {
   var field;
   for (var name in fields) {
-    if (!fields.hasOwnProperty(name)) { continue; }
-
-    field = fields[name];
-    // important to append ReadStreams within the same tick
-    if ((typeof field.value == 'function')) {
-      field.value = field.value();
+    if (Object.prototype.hasOwnProperty.call(fields, name)) {
+      field = fields[name];
+      // important to append ReadStreams within the same tick
+      if ((typeof field.value == 'function')) {
+        field.value = field.value();
+      }
+      form.append(name, field.value);
     }
-    form.append(name, field.value);
   }
 };
 
diff --git a/test/integration/test-custom-content-type.js b/test/integration/test-custom-content-type.js
index d8c1b765..534fdfbd 100644
--- a/test/integration/test-custom-content-type.js
+++ b/test/integration/test-custom-content-type.js
@@ -67,16 +67,15 @@ server.listen(common.port, function() {
 
   var form = new FormData();
 
-  var field;
   for (var name in FIELDS) {
-    if (!FIELDS.hasOwnProperty(name)) { continue; }
-
-    field = FIELDS[name];
-    // important to append ReadStreams within the same tick
-    if ((typeof field.value == 'function')) {
-      field.value = field.value();
+    if (Object.prototype.hasOwnProperty.call(FIELDS, name)) {
+      var field = FIELDS[name];
+      // important to append ReadStreams within the same tick
+      if ((typeof field.value == 'function')) {
+        field.value = field.value();
+      }
+      form.append(name, field.value, field.options);
     }
-    form.append(name, field.value, field.options);
   }
 
   // custom params object passed to submit
diff --git a/test/integration/test-pipe.js b/test/integration/test-pipe.js
index c3360efc..1b41a02b 100644
--- a/test/integration/test-pipe.js
+++ b/test/integration/test-pipe.js
@@ -49,16 +49,15 @@ server.listen(common.port, function() {
 
   var form = new FormData();
 
-  var field;
   for (var name in FIELDS) {
-    if (!FIELDS.hasOwnProperty(name)) { continue; }
-
-    field = FIELDS[name];
-    // important to append ReadStreams within the same tick
-    if ((typeof field.value == 'function')) {
-      field.value = field.value();
+    if (Object.prototype.hasOwnProperty.call(FIELDS, name)) {
+      var field = FIELDS[name];
+      // important to append ReadStreams within the same tick
+      if ((typeof field.value == 'function')) {
+        field.value = field.value();
+      }
+      form.append(name, field.value);
     }
-    form.append(name, field.value);
   }
 
   var req = http.request({
diff --git a/test/integration/test-ranged-filestream.js b/test/integration/test-ranged-filestream.js
index bac1d259..8fa0cafe 100644
--- a/test/integration/test-ranged-filestream.js
+++ b/test/integration/test-ranged-filestream.js
@@ -80,20 +80,18 @@ server.listen(common.port, function() {
 
   // add test subjects to the form
   for (name in testSubjects) {
-    if (!testSubjects.hasOwnProperty(name)) {
-      continue;
-    }
-
-    options = {encoding: 'utf8'};
+    if (Object.prototype.hasOwnProperty.call(testSubjects, name)) {
+      options = {encoding: 'utf8'};
 
-    if (testSubjects[name].start) { options.start = testSubjects[name].start; }
-    if (testSubjects[name].end) { options.end = testSubjects[name].end; }
+      if (testSubjects[name].start) { options.start = testSubjects[name].start; }
+      if (testSubjects[name].end) { options.end = testSubjects[name].end; }
 
-    form.append(name, testSubjects[name].fsStream = fs.createReadStream(common.dir.fixture + '/' + testSubjects[name].file, options));
+      form.append(name, testSubjects[name].fsStream = fs.createReadStream(common.dir.fixture + '/' + testSubjects[name].file, options));
 
-    // calculate data size
-    testSubjects[name].readSize = 0;
-    testSubjects[name].fsStream.on('data', readSizeAccumulator.bind(testSubjects[name]));
+      // calculate data size
+      testSubjects[name].readSize = 0;
+      testSubjects[name].fsStream.on('data', readSizeAccumulator.bind(testSubjects[name]));
+    }
   }
 
   form.submit('http://localhost:' + common.port + '/', function(err, res) {