diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
new file mode 100644
index 0000000..d8099b3
--- /dev/null
+++ b/.github/workflows/build.yaml
@@ -0,0 +1,22 @@
+name: Build and test pandajs
+
+on: [push, pull_request]
+
+jobs:
+  build_test:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/cache@v2
+        id: yarn-cache
+        with:
+          path: node_modules
+          key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-yarn-
+      - if: steps.yarn-cache.outputs.cache-hit != 'true'
+        run: |
+          yarn install --ignore-scripts
+          yarn add --ignore-scripts usb
+      - run: yarn build
+      - run: yarn test
diff --git a/README.md b/README.md
index ec01cd8..bb3693d 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ or
 import Panda from '@commaai/pandajs';
 
 // create instance
-var panda = new Panda();
+const panda = new Panda();
 
 // register listener
 panda.onMessage((msg) => {
diff --git a/control-panda.js b/control-panda.js
index 7e8412a..b5b0ea0 100755
--- a/control-panda.js
+++ b/control-panda.js
@@ -3,7 +3,6 @@
 const cli = require('commander');
 const PandaLib = require('./lib');
 const Panda = PandaLib.default;
-const wait = require('./src/delay');
 const package = require('./package');
 
 cli
@@ -57,7 +56,7 @@ if (!process.argv.slice(2).length) {
   cli.help();
 }
 
-var safetyModes = [];
+const safetyModes = [];
 Object.keys(PandaLib).forEach(function (key) {
   if (key.startsWith('SAFETY_')) {
     safetyModes.push(key.substr(7).toLowerCase());
@@ -67,7 +66,7 @@ Object.keys(PandaLib).forEach(function (key) {
 cli.parse(process.argv);
 
 async function setupPanda () {
-  var panda = new Panda({
+  const panda = new Panda({
     wifi: cli.wifi
   });
 
@@ -84,37 +83,37 @@ async function setupPanda () {
 
 // command implementations
 async function getVersion () {
-  var panda = await setupPanda();
-  var result = await panda.getVersion();
+  const panda = await setupPanda();
+  const result = await panda.getVersion();
   console.log(result);
 }
 async function getSecret () {
-  var panda = await setupPanda();
-  var result = await panda.getSecret();
+  const panda = await setupPanda();
+  const result = await panda.getSecret();
   console.log(result);
 }
 
 async function isWhite () {
-  var panda = await setupPanda();
-  var result = await panda.isWhite();
+  const panda = await setupPanda();
+  const result = await panda.isWhite();
   console.log('is white:', result);
 }
 
 async function isGrey () {
-  var panda = await setupPanda();
-  var result = await panda.isGrey();
+  const panda = await setupPanda();
+  const result = await panda.isGrey();
   console.log('is grey:', result);
 }
 
 async function isBlack () {
-  var panda = await setupPanda();
-  var result = await panda.isBlack();
+  const panda = await setupPanda();
+  const result = await panda.isBlack();
   console.log('is black:', result);
 }
 
 async function hasObd () {
-  var panda = await setupPanda();
-  var result = await panda.hasObd();
+  const panda = await setupPanda();
+  const result = await panda.hasObd();
   console.log('has OBD port:', result);
 }
 
@@ -125,8 +124,8 @@ async function setObd (connected, cmd) {
   }
   obd = connected === "true" || connected === "1";
   console.log('OBD port:', obd ? 'connected' : 'disconnected');
-  var panda = await setupPanda();
-  var result = await panda.setObd(obd);
+  const panda = await setupPanda();
+  const result = await panda.setObd(obd);
   console.log(result);
 }
 
@@ -135,21 +134,21 @@ async function setSafetyMode (mode, cmd) {
     console.error('Safety mode must be one of the following:', '\n\t' + safetyModes.join('\n\t'));
     return;
   }
-  var modeConst = PandaLib['SAFETY_' + mode.toUpperCase()];
+  const modeConst = PandaLib['SAFETY_' + mode.toUpperCase()];
   console.log('Activing safety mode:', mode, '(0x' + modeConst.toString(16) + ')');
-  var panda = await setupPanda();
-  var result = await panda.setSafetyMode(modeConst);
+  const panda = await setupPanda();
+  const result = await panda.setSafetyMode(modeConst);
   console.log(result);
 }
 
 async function getWifi () {
-  var panda = await setupPanda();
-  var result = await panda.getDeviceMetadata();
+  const panda = await setupPanda();
+  const result = await panda.getDeviceMetadata();
   console.log('SID: panda-' + result[0]);
   console.log('Password:', result[1]);
 }
 
 async function getHealth () {
-  var panda = await setupPanda();
+  const panda = await setupPanda();
   console.log(await panda.getHealth());
 }
diff --git a/dump-can.js b/dump-can.js
index e918ccd..15b1408 100755
--- a/dump-can.js
+++ b/dump-can.js
@@ -15,7 +15,7 @@ cli
   .option('-i, --index <i>', 'Choose a different connected panda than the first one (zero indexed)', parseInt)
   .parse(process.argv);
 
-var panda = new Panda({
+const panda = new Panda({
   wifi: cli.wifi,
   selectDevice: (devices) => {
     return devices[Math.min(devices.length, cli.index || 0)];
@@ -62,7 +62,7 @@ connectAndRun();
 async function connectAndRun () {
   await panda.connect();
   if (cli.health) {
-    var health = await panda.getHealth();
+    const health = await panda.getHealth();
     console.log(health);
     console.log('Connect finished, waiting then reading all messages...');
     await wait(1000);
diff --git a/src/browser.js b/src/browser.js
index 5c6e845..3ee3f33 100644
--- a/src/browser.js
+++ b/src/browser.js
@@ -24,7 +24,7 @@ export const SAFETY_HONDA_BOSCH_HARNESS = 20;
 export default function Panda (options) {
   options = options || {};
 
-  var device = new PandaDevice(options, navigator.usb);
+  const device = new PandaDevice(options, navigator.usb);
   options.device = device;
   return new PandaAPI(options);
 }
diff --git a/src/delay.js b/src/delay.js
index a208257..767480a 100644
--- a/src/delay.js
+++ b/src/delay.js
@@ -1,34 +1,34 @@
 'use strict';
 
 class CancelError extends Error {
-	constructor(message) {
-		super(message);
-		this.name = 'CancelError';
-	}
+  constructor(message) {
+    super(message);
+    this.name = 'CancelError';
+  }
 }
 
 const createDelay = willResolve => (ms, value) => {
-	let timeoutId;
-	let internalReject;
+  let timeoutId;
+  let internalReject;
 
-	const delayPromise = new Promise((resolve, reject) => {
-		internalReject = reject;
+  const delayPromise = new Promise((resolve, reject) => {
+    internalReject = reject;
 
-		timeoutId = setTimeout(() => {
-			const settle = willResolve ? resolve : reject;
-			settle(value);
-		}, ms);
-	});
+    timeoutId = setTimeout(() => {
+      const settle = willResolve ? resolve : reject;
+      settle(value);
+    }, ms);
+  });
 
-	delayPromise.cancel = () => {
-		if (timeoutId) {
-			clearTimeout(timeoutId);
-			timeoutId = null;
-			internalReject(new CancelError('Delay canceled'));
-		}
-	};
+  delayPromise.cancel = () => {
+    if (timeoutId) {
+      clearTimeout(timeoutId);
+      timeoutId = null;
+      internalReject(new CancelError('Delay canceled'));
+    }
+  };
 
-	return delayPromise;
+  return delayPromise;
 };
 
 module.exports = createDelay(true);
diff --git a/src/impl/browser.js b/src/impl/browser.js
index 4cef889..93b2c3e 100644
--- a/src/impl/browser.js
+++ b/src/impl/browser.js
@@ -1,7 +1,6 @@
-import { packCAN, unpackCAN } from 'can-message';
+import { packCAN } from 'can-message';
 import Event from 'weakmap-event';
 import { partial } from 'ap';
-import now from 'performance-now';
 import wait from '../delay';
 
 const PANDA_VENDOR_ID = 0xbbaa;
@@ -54,12 +53,11 @@ export default class Panda {
       index: data.index
     };
 
-    var result = await this.device.controlTransferIn(controlParams, length);
-    result = {
+    const result = await this.device.controlTransferIn(controlParams, length);
+    return {
       data: Buffer.from(result.data.buffer),
       status: result.status
     };
-    return result;
   }
 
   async vendorWrite(data, length) {
@@ -90,8 +88,8 @@ export default class Panda {
   }
 
   async nextMessage() {
-    var result = null;
-    var attempts = 0;
+    let result = null;
+    let attempts = 0;
 
     while (result === null) {
       try {
diff --git a/src/impl/node.js b/src/impl/node.js
index db2b488..ebe0825 100644
--- a/src/impl/node.js
+++ b/src/impl/node.js
@@ -1,8 +1,7 @@
 import USB from 'usb';
-import { packCAN, unpackCAN } from 'can-message';
+import { packCAN } from 'can-message';
 import Event from 'weakmap-event';
 import { partial } from 'ap';
-import now from 'performance-now';
 import wait from '../delay';
 import isPromise from 'is-promise';
 
@@ -26,9 +25,7 @@ export default class Panda {
   }
 
   async findDevice() {
-    var devices = USB.getDeviceList();
-
-    devices = devices.filter((device) => {
+    const devices = USB.getDeviceList().filter((device) => {
       return device.deviceDescriptor.idVendor === PANDA_VENDOR_ID;
     });
 
@@ -36,7 +33,7 @@ export default class Panda {
   }
   async selectDevice(devices) {
     return new Promise((resolve, reject) => {
-      var result = this.selectDeviceMethod(devices, resolve);
+      const result = this.selectDeviceMethod(devices, resolve);
 
       if (result) {
         if (isPromise(result)) {
@@ -141,7 +138,7 @@ export default class Panda {
     endpointNumber = endpointNumber | 0x80;
 
     return new Promise(async (resolve, reject) => {
-      var endpoint = null;
+      let endpoint = null;
       this.device.interfaces.some(iface => {
         const epoint = iface.endpoint(endpointNumber);
 
@@ -151,19 +148,19 @@ export default class Panda {
         }
       });
       if (!endpoint) {
-        let err = new Error('PandaJS: nodeusb: transferIn failed to find endpoint interface ' + endpointNumber);
+        const err = new Error('PandaJS: nodeusb: transferIn failed to find endpoint interface ' + endpointNumber);
         ErrorEvent.broadcast(this, err);
         return reject(err);
       }
       if (endpoint.direction !== 'in') {
-        let err = new Error('PandaJS: nodeusb: endpoint interface is ' + endpoint.direction + ' instead of in');
+        const err = new Error('PandaJS: nodeusb: endpoint interface is ' + endpoint.direction + ' instead of in');
         ErrorEvent.broadcast(this, err);
         return reject(err);
       }
-      var data = Buffer.from([]);
-      while (data.length === 0) {
+      let data;
+      do {
         data = await this.endpointTransfer(endpoint, length);
-      }
+      } while (data.length === 0);
       resolve(data);
     });
   }
@@ -180,10 +177,9 @@ export default class Panda {
   }
 
   async nextMessage() {
-    var result = null;
-    var attempts = 0;
+    let attempts = 0;
 
-    while (result === null) {
+    while (true) {
       try {
         return await this.transferIn(1, BUFFER_SIZE);
       } catch (err) {
diff --git a/src/impl/node.test.js b/src/impl/node.test.js
index 17f246d..2424f50 100644
--- a/src/impl/node.test.js
+++ b/src/impl/node.test.js
@@ -8,7 +8,7 @@ const desiredDeviceString = 'it worked';
 const deviceList = [false, false, desiredDeviceString, false];
 
 test('selectDevice can return any way', async function (t) {
-  var panda = new PandaNode({
+  let panda = new PandaNode({
     selectDevice: selectDeviceReturn
   });
   t.equals(await panda.selectDevice(deviceList), desiredDeviceString, 'works when returning directly');
diff --git a/src/impl/wifi.js b/src/impl/wifi.js
index 6b85ab0..61ef8b6 100644
--- a/src/impl/wifi.js
+++ b/src/impl/wifi.js
@@ -1,11 +1,8 @@
-import USB from 'usb';
-import { packCAN, unpackCAN } from 'can-message';
+import { packCAN } from 'can-message';
 import Event from 'weakmap-event';
 import { partial } from 'ap';
 import wait from '../delay';
-import isPromise from 'is-promise';
 import net from 'net';
-import dgram from 'dgram';
 
 const PANDA_MESSAGE_ENDPOINT_NUMBER = 1;
 const PANDA_HOST = '192.168.0.10';
@@ -33,12 +30,12 @@ export default class Panda {
   }
   async connectToTCP() {
     return new Promise((resolve, reject) => {
-      var fail = (err) => {
+      const fail = (err) => {
         this.socket = null;
         ErrorEvent.broadcast(this, err);
         reject(err);
       };
-      var succeed = () => {
+      const succeed = () => {
         this.socket.off('close', fail);
         this.socket.off('error', fail);
         resolve();
@@ -72,9 +69,9 @@ export default class Panda {
   }
 
   async vendorRequest(data, length) {
-    var data = await this.controlRead(REQUEST_OUT, data.request, data.value, data.index, length);
+    const response = await this.controlRead(REQUEST_OUT, data.request, data.value, data.index, length);
     return {
-      data: Buffer.from(data),
+      data: Buffer.from(response),
       status: "ok" // hack, find out when it's actually ok
     };
   }
@@ -124,10 +121,9 @@ export default class Panda {
   }
 
   async nextMessage() {
-    var result = null;
-    var attempts = 0;
+    let attempts = 0;
 
-    while (result === null) {
+    while (true) {
       try {
         return await this.bulkRead(1);
       } catch (err) {
@@ -161,24 +157,24 @@ export default class Panda {
   }
 
   async bulkRead(endpoint: Number, timeoutMillis: Number = 0) {
-      const promise = this.nextIncomingMessage();
+    const promise = this.nextIncomingMessage();
 
-      const buf = Buffer.alloc(4);
-      buf.writeUInt16LE(endpoint, 0);
-      buf.writeUInt16LE(0, 2);
-      this.socket.write(buf);
+    const buf = Buffer.alloc(4);
+    buf.writeUInt16LE(endpoint, 0);
+    buf.writeUInt16LE(0, 2);
+    this.socket.write(buf);
 
-      return promise;
+    return promise;
   }
 }
 
 function once (event, handler) {
-  var unlisten = event(onceHandler);
-
-  return unlisten;
+  const unlisten = event(onceHandler);
 
   function onceHandler() {
     unlisten();
     handler.apply(this, arguments);
   }
+
+  return unlisten;
 }
diff --git a/src/index.js b/src/index.js
index 2aaeb92..1e1aaee 100644
--- a/src/index.js
+++ b/src/index.js
@@ -25,7 +25,7 @@ export default function Panda (options) {
   options = options || {};
   options.selectDevice = options.selectDevice || selectFirstDevice;
 
-  var device = new PandaDevice(options);
+  const device = new PandaDevice(options);
   options.device = device;
   return new PandaAPI(options);
 }
diff --git a/src/panda-device.js b/src/panda-device.js
index f13121e..4c4b3ac 100644
--- a/src/panda-device.js
+++ b/src/panda-device.js
@@ -1,23 +1,22 @@
-
 export default function PandaUSB (options) {
   if (require('is-browser')) {
     if (options.wifi) {
       throw new Error('You cannot use wifi mode in the browser.');
     }
-    let PandaWebUSB = require('./impl/browser').default;
+    const PandaWebUSB = require('./impl/browser').default;
     return new PandaWebUSB(options, navigator.usb);
   }
   if (options.wifi) {
-    let PandaWifi = require('./impl/wifi').default;
+    const PandaWifi = require('./impl/wifi').default;
     return new PandaWifi(options);
   }
   // check for test before node since tests always run in node
   if (isTestEnv()) {
-    let PandaMock = require('./impl/mock').default;
+    const PandaMock = require('./impl/mock').default;
     return new PandaMock(options);
   }
   if (require('is-node')) {
-    let PandaNodeUSB = require('./impl/node').default;
+    const PandaNodeUSB = require('./impl/node').default;
     return new PandaNodeUSB(options);
   }
   console.log(process.env);
diff --git a/src/panda.js b/src/panda.js
index 41acd9f..cab2150 100644
--- a/src/panda.js
+++ b/src/panda.js
@@ -1,4 +1,4 @@
-import { packCAN, unpackCAN } from 'can-message';
+import { unpackCAN } from 'can-message';
 import Event from 'weakmap-event';
 import { partial } from 'ap';
 import now from 'performance-now';
@@ -53,7 +53,7 @@ export default class Panda {
     }
     await this.device.connect();
 
-    var serialNumber = await this.getSerialNumber();
+    const serialNumber = await this.getSerialNumber();
     this.connectHandler(serialNumber);
 
     return serialNumber;
@@ -69,7 +69,7 @@ export default class Panda {
     return this.unpause();
   }
   async pause() {
-    var wasPaused = this.isPaused();
+    const wasPaused = this.isPaused();
     this.paused = true;
 
     return !wasPaused;
@@ -78,7 +78,7 @@ export default class Panda {
     return this.unpause();
   }
   async unpause() {
-    var wasPaused = this.isPaused();
+    const wasPaused = this.isPaused();
     if (!wasPaused) {
       return false;
     }
@@ -91,53 +91,45 @@ export default class Panda {
 
   // vendor API methods
   async getHealth() {
-    let buf = await this.vendorRequest('health', {
+    const buf = await this.vendorRequest('health', {
       request: 0xd2,
       value: 0,
       index: 0
     }, 13);
 
-    let voltage = buf.readUInt32LE(0) / 1000;
-    let current = buf.readUInt32LE(4) / 1000;
-    let isStarted = buf.readInt8(8) === 1;
-    let controlsAreAllowed = buf.readInt8(9) === 1;
-    let isGasInterceptorDetector = buf.readInt8(10) === 1;
-    let isStartSignalDetected = buf.readInt8(11) === 1;
-    let isStartedAlt = buf.readInt8(12) === 1;
-
     return {
-      voltage,
-      current,
-      isStarted,
-      controlsAreAllowed,
-      isGasInterceptorDetector,
-      isStartSignalDetected,
-      isStartedAlt
+      voltage: buf.readUInt32LE(0) / 1000,
+      current: buf.readUInt32LE(4) / 1000,
+      isStarted: buf.readInt8(8) === 1,
+      controlsAreAllowed: buf.readInt8(9) === 1,
+      isGasInterceptorDetector: buf.readInt8(10) === 1,
+      isStartSignalDetected: buf.readInt8(11) === 1,
+      isStartedAlt: buf.readInt8(12) === 1
     };
   }
   async getDeviceMetadata() {
-    let buf = await this.vendorRequest('getDeviceMetadata', {
+    const buf = await this.vendorRequest('getDeviceMetadata', {
       request: 0xd0,
       value: 0,
       index: 0
     }, 0x20);
 
-    let serial = buf.slice(0, 0x10); // serial is the wifi style serial
-    let secret = buf.slice(0x10, 0x10 + 10);
-    let hashSig = buf.slice(0x1c);
+    const serial = buf.slice(0, 0x10); // serial is the wifi style serial
+    const secret = buf.slice(0x10, 0x10 + 10);
+    const hashSig = buf.slice(0x1c);
 
     return [serial.toString(), secret.toString()];
   }
   async getSerialNumber() {
-    var [serial, secret] = await this.getDeviceMetadata();
+    const [serial, secret] = await this.getDeviceMetadata();
     return serial;
   }
   async getSecret() {
-    var [serial, secret] = await this.getDeviceMetadata();
+    const [serial, secret] = await this.getDeviceMetadata();
     return secret;
   }
   async getVersion() {
-    let buf = await this.vendorRequest('getVersion', {
+    const buf = await this.vendorRequest('getVersion', {
       request: 0xd6,
       value: 0,
       index: 0
@@ -146,7 +138,7 @@ export default class Panda {
     return buf.toString();
   }
   async getType() {
-    let buf = await this.vendorRequest('getType', {
+    const buf = await this.vendorRequest('getType', {
       request: 0xc1,
       value: 0,
       index: 0
@@ -184,7 +176,7 @@ export default class Panda {
   // i/o wrappers
   async vendorRequest (event, controlParams, length) {
     try {
-      let result = await this.device.vendorRequest(controlParams, length);
+      const result = await this.device.vendorRequest(controlParams, length);
 
       return result.data;
     } catch (err) {
@@ -197,7 +189,7 @@ export default class Panda {
       message = Buffer.from([]);
     }
     try {
-      let result = await this.device.vendorWrite(controlParams, message);
+      const result = await this.device.vendorWrite(controlParams, message);
 
       return result.data;
     } catch (err) {
@@ -225,7 +217,7 @@ export default class Panda {
       return this.flushEvent;
     }
 
-    var unlisten = raf(this.flushMessageQueue);
+    const unlisten = raf(this.flushMessageQueue);
 
     this.flushEvent = () => {
       raf.cancel(unlisten);
@@ -238,7 +230,7 @@ export default class Panda {
     this.flushEvent();
 
     if (this.needsFlush && this.messageQueue.length) {
-      let messageQueue = this.messageQueue;
+      const messageQueue = this.messageQueue;
       this.messageQueue = [];
       this.needsFlush = false;
       MessageEvent.broadcast(this, messageQueue);
@@ -265,9 +257,9 @@ export default class Panda {
     this.isReading = true;
 
     for (let i = 0; i < MAX_MESSAGE_QUEUE; ++i) {
-      let data = await this.device.nextMessage();
-      let receiptTime = now() / 1000
-      let canMessages = unpackCAN(data);
+      const data = await this.device.nextMessage();
+      const receiptTime = now() / 1000
+      const canMessages = unpackCAN(data);
       if (!canMessages.length) {
         await wait(1);
         continue;
diff --git a/src/test.js b/src/test.js
index fdefebb..dd4faec 100644
--- a/src/test.js
+++ b/src/test.js
@@ -8,9 +8,9 @@ test('is valid', (t) => {
 });
 
 test('manages connection state correctly, starts paused', async function(t) {
-  var panda = new PandaJS();
+  const panda = new PandaJS();
 
-  var usbId = await panda.connect();
+  const usbId = await panda.connect();
   t.ok(usbId, 'gets a USB id from connect');
   t.equals(panda.isConnected(), true);
   t.equals(panda.isPaused(), true);
@@ -23,9 +23,9 @@ test('manages connection state correctly, starts paused', async function(t) {
 
 
 test('re-pauses when disconnected', async function(t) {
-  var panda = new PandaJS();
+  const panda = new PandaJS();
 
-  var usbId = await panda.start();
+  const usbId = await panda.start();
   t.ok(usbId, 'gets a USB id from start');
   t.equals(panda.isConnected(), true, 'is connected state after connecting');
   t.equals(panda.isPaused(), false, 'starts unpaused when start is used');