diff --git a/lib/autohttp/agent.js b/lib/autohttp/agent.js
index 7c7315b11..75402c00b 100644
--- a/lib/autohttp/agent.js
+++ b/lib/autohttp/agent.js
@@ -57,10 +57,12 @@ class AutoHttp2Agent extends EventEmitter {
     cb,
     socketCb
   ) {
-    const options = Object.assign({}, reqOptions, this.options, {
+    const options = {
+      ...reqOptions,
+      ...this.options,
       port: Number(reqOptions.port || this.options.port || this.defaultPort),
       host: reqOptions.hostname || reqOptions.host || 'localhost'
-    })
+    }
 
     // check if ALPN is cached
     const name = getSocketName(options)
@@ -76,9 +78,10 @@ class AutoHttp2Agent extends EventEmitter {
     // No need to pass the cachedSocket since the respective protocol's agents will reuse the socket that was initially
     // passed during ALPN Negotiation
     if (protocol === 'h2') {
-      const http2Options = Object.assign({}, options, {
+      const http2Options = {
+        ...options,
         path: options.socketPath
-      })
+      }
 
       let connection
       try {
@@ -96,9 +99,10 @@ class AutoHttp2Agent extends EventEmitter {
       return
     }
 
-    const http1RequestOptions = Object.assign({}, options, {
+    const http1RequestOptions = {
+      ...options,
       agent: this.httpsAgent
-    })
+    }
 
     let request
     try {
@@ -116,11 +120,12 @@ class AutoHttp2Agent extends EventEmitter {
     const uri = options.uri
     const name = getSocketName(options)
 
-    const socket = tls.connect(Object.assign({}, options, {
+    const socket = tls.connect({
+      ...options,
       path: options.socketPath,
       ALPNProtocols: supportedProtocols,
       servername: options.servername || calculateServerName(options)
-    }))
+    })
     socketCb(socket)
 
     const socketConnectionErrorHandler = (e) => {
@@ -153,9 +158,10 @@ class AutoHttp2Agent extends EventEmitter {
       })
 
       if (protocol === 'h2') {
-        const http2Options = Object.assign({}, options, {
+        const http2Options = {
+          ...options,
           path: options.socketPath
-        })
+        }
         try {
           const connection = this.http2Agent.createConnection(
             req,
@@ -182,9 +188,10 @@ class AutoHttp2Agent extends EventEmitter {
         return socket
       }
 
-      const http1RequestOptions = Object.assign({}, options, {
+      const http1RequestOptions = {
+        ...options,
         agent: this.httpsAgent
-      })
+      }
       let request
       try {
         request = https.request(http1RequestOptions)
diff --git a/lib/autohttp/request.js b/lib/autohttp/request.js
index 788ecc93c..8b12466b9 100644
--- a/lib/autohttp/request.js
+++ b/lib/autohttp/request.js
@@ -36,11 +36,12 @@ class MultiProtocolRequest extends EventEmitter {
   }
 
   onHttp2 (connection) {
-    const options = Object.assign({}, this.options, {
+    const options = {
+      ...this.options,
       agent: {
         createConnection: () => connection
       }
-    })
+    }
 
     let req
     try {
diff --git a/lib/http2/agent.js b/lib/http2/agent.js
index 91c74f234..464f5f720 100644
--- a/lib/http2/agent.js
+++ b/lib/http2/agent.js
@@ -10,17 +10,22 @@ class Http2Agent extends EventEmitter {
   }
 
   createConnection (req, uri, options, socket) {
-    const _options = Object.assign({}, options, this.options)
+    const _options = {
+      ...options,
+      ...this.options
+    }
+
     const name = getConnectionName(_options)
     let connection = this.connections[name]
 
     if (!connection || connection.destroyed || connection.closed) {
-      const connectionOptions = Object.assign({}, _options,
-        {
-          port: _options.port || 443,
-          settings: {
-            enablePush: false
-          } })
+      const connectionOptions = {
+        ..._options,
+        port: _options.port || 443,
+        settings: {
+          enablePush: false
+        }
+      }
 
       // check if a socket is supplied
       if (socket) {
diff --git a/lib/http2/request.js b/lib/http2/request.js
index b742cdd2f..1568b0822 100644
--- a/lib/http2/request.js
+++ b/lib/http2/request.js
@@ -42,14 +42,13 @@ class Http2Request extends EventEmitter {
     this._flushHeaders = this._flushHeaders.bind(this)
     this[kHeadersFlushed] = false
 
-    const headers = options.headers || {}
-
     const uri = httpOptionsToUri(options)
-    const _options = Object.assign({}, options, {
+    const _options = {
+      ...options,
       port: Number(options.port || 443),
       path: undefined,
       host: options.hostname || options.host || 'localhost'
-    })
+    }
 
     if (options.socketPath) {
       _options.path = options.socketPath
@@ -59,19 +58,23 @@ class Http2Request extends EventEmitter {
 
     this._client = agent.createConnection(this, uri, _options)
 
-    this.requestHeaders = Object.assign(headers, {
+    const headers = options.headers || {}
+
+    this.requestHeaders = {
+      ...headers,
       [http2.constants.HTTP2_HEADER_PATH]: options.path || '/',
       [http2.constants.HTTP2_HEADER_METHOD]: _options.method,
       [http2.constants.HTTP2_HEADER_AUTHORITY]: headers['host'] || _options.host
-    })
+    }
 
     if (options.uri.isUnix || headers['host'] === 'unix' || _options.host === 'unix') {
       // The authority field needs to be set to 'localhost' when using unix sockets.
       // The default URL parser supplies the isUnix flag when the host is 'unix'. Added other checks incase using a different parser like WHATWG URL (new URL()).
       // See: https://github.com/nodejs/node/issues/32326
-      this.requestHeaders = Object.assign(this.requestHeaders, {
+      this.requestHeaders = {
+        ...this.requestHeaders,
         [http2.constants.HTTP2_HEADER_AUTHORITY]: 'localhost'
-      })
+      }
     }
 
     this.socket = this._client.socket
diff --git a/package.json b/package.json
index bb8b3b561..41b9a250e 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,7 @@
   "devDependencies": {
     "bluebird": "^3.2.1",
     "browserify": "^16.5.2",
-    "browserify-istanbul": "^2.0.0",
+    "browserify-istanbul": "^3.0.0",
     "buffer-equal": "^1.0.1",
     "codecov": "^3.0.4",
     "coveralls": "^3.0.2",