diff --git a/.eslintignore b/.eslintignore
index 10f501cc..07fcb643 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,3 +1,3 @@
 node_modules
 coverage/
-/packages/generator-open-wc/generators/*/templates/**/*
\ No newline at end of file
+/packages/generator-open-wc/generators/*/templates/**/*
diff --git a/.eslintrc.js b/.eslintrc.js
index a018cc01..182ffc2d 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,5 +1,6 @@
 module.exports = {
   extends: [
     './packages/eslint-config/index.js',
+    require.resolve('eslint-config-prettier'),
   ],
 };
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 00000000..07fcb643
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,3 @@
+node_modules
+coverage/
+/packages/generator-open-wc/generators/*/templates/**/*
diff --git a/husky.config.js b/husky.config.js
index 718bbcd8..4c2ec3ae 100644
--- a/husky.config.js
+++ b/husky.config.js
@@ -1,6 +1,6 @@
 module.exports = {
   hooks: {
-    'pre-commit': 'npm run lint',
+    'pre-commit': 'lint-staged',
     'commit-msg': 'commitlint -E HUSKY_GIT_PARAMS',
   },
 };
diff --git a/package.json b/package.json
index 3c6fa174..bea239bd 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
     "bootstrap": "lerna bootstrap --hoist --no-ci",
     "lint": "run-p lint:*",
     "lint:eslint": "eslint --ext .js,.html .",
+    "lint:prettier": "prettier packages/**/*.js --write",
     "publish": "lerna publish --message 'chore: release new versions'",
     "site:build": "npm run vuepress:build",
     "site:start": "npm run vuepress:start",
@@ -15,13 +16,23 @@
     "vuepress:build": "vuepress build docs",
     "vuepress:start": "vuepress dev docs"
   },
+  "lint-staged": {
+    "*.js": [
+      "eslint --fix",
+      "prettier --write",
+      "git add"
+    ]
+  },
   "devDependencies": {
     "@commitlint/cli": "7.2.1",
     "@commitlint/config-conventional": "7.1.2",
     "@commitlint/config-lerna-scopes": "7.2.1",
+    "eslint-config-prettier": "^3.3.0",
     "husky": "1.1.2",
     "lerna": "3.4.3",
+    "lint-staged": "^8.1.0",
     "npm-run-all": "4.1.3",
+    "prettier": "^1.15.0",
     "vuepress": "1.0.0-alpha.18"
   }
 }
diff --git a/packages/chai-dom-equals/chai-dom-equals.js b/packages/chai-dom-equals/chai-dom-equals.js
index dc628466..639e209d 100644
--- a/packages/chai-dom-equals/chai-dom-equals.js
+++ b/packages/chai-dom-equals/chai-dom-equals.js
@@ -4,11 +4,11 @@ import { getSemanticDomDiff } from '@open-wc/semantic-dom-diff';
  * el.outerHTML is not polyfilled so we need to recreate the tag + attributes and
  * combine it with el.innerHTML.
  */
-export const getOuterHtml = (el) => {
+export const getOuterHtml = el => {
   if (window.ShadyCSS && window.ShadyCSS.nativeShadow === false) {
     const tagName = el.tagName.toLowerCase();
     let attributes = ' ';
-    Array.prototype.slice.call(el.attributes).forEach((item) => {
+    Array.prototype.slice.call(el.attributes).forEach(item => {
       attributes += `${item.name}="${item.value}" `;
     });
     // removes last ' ' or if there are no attributes makes it to equal ''
@@ -22,7 +22,7 @@ export const getOuterHtml = (el) => {
  * For comparision we do not need the style scoping classes on polyfilled browsers
  * Rather naive approach for now - probably need to improve once we have failing cases.
  */
-export const getCleanedShadowDom = (el) => {
+export const getCleanedShadowDom = el => {
   if (window.ShadyCSS && window.ShadyCSS.nativeShadow === false) {
     const tagName = el.tagName.toLowerCase();
     const regexTagName = new RegExp(tagName, 'g');
@@ -56,6 +56,7 @@ export const chaiDomEquals = (chai, utils) => {
   });
 
   // can not be an arrow function as it gets rebound
+  // prettier-ignore
   const domEquals = _super => function handleDom(value, ...args) {
     if (!utils.flag(this, 'semantically') && utils.flag(this, 'dom')) {
       const expected = getOuterHtml(this._obj);
diff --git a/packages/chai-dom-equals/karma.conf.js b/packages/chai-dom-equals/karma.conf.js
index 4c5ef9c2..2902a8de 100644
--- a/packages/chai-dom-equals/karma.conf.js
+++ b/packages/chai-dom-equals/karma.conf.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma/create-karma-config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/chai-dom-equals/karma.es5.bs.config.js b/packages/chai-dom-equals/karma.es5.bs.config.js
index 04305582..b0e0b847 100644
--- a/packages/chai-dom-equals/karma.es5.bs.config.js
+++ b/packages/chai-dom-equals/karma.es5.bs.config.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma-bs/create-karma-es5-bs.config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/chai-dom-equals/wallaby.js b/packages/chai-dom-equals/wallaby.js
index 694b0ed9..2efec33f 100644
--- a/packages/chai-dom-equals/wallaby.js
+++ b/packages/chai-dom-equals/wallaby.js
@@ -5,9 +5,7 @@ const wallabyPostprocessor = wallabyWebpack({
   resolve: {
     modules: [path.resolve(__dirname, 'bower_components'), 'node_modules'],
   },
-  entryPatterns: [
-    'test/index.js',
-  ],
+  entryPatterns: ['test/index.js'],
 });
 
 module.exports = () => ({
@@ -19,15 +17,14 @@ module.exports = () => ({
     { pattern: 'test/index.js', load: false },
     { pattern: 'test/*.test.js', ignore: true },
   ],
-  tests: [
-    { pattern: 'test/*.test.js', load: false },
-  ],
+  tests: [{ pattern: 'test/*.test.js', load: false }],
   testFramework: 'mocha',
   debug: true,
   env: {
     kind: 'chrome',
     params: {
-      runner: '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
+      runner:
+        '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
     },
   },
   postprocessor: wallabyPostprocessor,
diff --git a/packages/eslint-config/index.js b/packages/eslint-config/index.js
index 470739f6..0233c68d 100644
--- a/packages/eslint-config/index.js
+++ b/packages/eslint-config/index.js
@@ -1,7 +1,5 @@
 module.exports = {
-  extends: [
-    'eslint-config-airbnb-base',
-  ].map(require.resolve),
+  extends: ['eslint-config-airbnb-base'].map(require.resolve),
   parser: 'babel-eslint',
   env: {
     browser: true,
@@ -11,12 +9,12 @@ module.exports = {
     'import/extensions': 'off',
     'no-underscore-dangle': 'off',
     'import/prefer-default-export': 'off',
-    'import/no-extraneous-dependencies': ['error', {
-      devDependencies: [
-        '**/test/*.js',
-        '**/stories/*.js',
-      ],
-    }],
+    'import/no-extraneous-dependencies': [
+      'error',
+      {
+        devDependencies: ['**/test/*.js', '**/stories/*.js'],
+      },
+    ],
   },
   settings: {
     'import/resolver': {
diff --git a/packages/semantic-dom-diff/karma.conf.js b/packages/semantic-dom-diff/karma.conf.js
index a9d8d2f9..287d9666 100644
--- a/packages/semantic-dom-diff/karma.conf.js
+++ b/packages/semantic-dom-diff/karma.conf.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma/create-karma-config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/semantic-dom-diff/karma.es5.bs.config.js b/packages/semantic-dom-diff/karma.es5.bs.config.js
index e22b6893..ad553e4c 100644
--- a/packages/semantic-dom-diff/karma.es5.bs.config.js
+++ b/packages/semantic-dom-diff/karma.es5.bs.config.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma-bs/create-karma-es5-bs.config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/semantic-dom-diff/wallaby.js b/packages/semantic-dom-diff/wallaby.js
index 694b0ed9..2efec33f 100644
--- a/packages/semantic-dom-diff/wallaby.js
+++ b/packages/semantic-dom-diff/wallaby.js
@@ -5,9 +5,7 @@ const wallabyPostprocessor = wallabyWebpack({
   resolve: {
     modules: [path.resolve(__dirname, 'bower_components'), 'node_modules'],
   },
-  entryPatterns: [
-    'test/index.js',
-  ],
+  entryPatterns: ['test/index.js'],
 });
 
 module.exports = () => ({
@@ -19,15 +17,14 @@ module.exports = () => ({
     { pattern: 'test/index.js', load: false },
     { pattern: 'test/*.test.js', ignore: true },
   ],
-  tests: [
-    { pattern: 'test/*.test.js', load: false },
-  ],
+  tests: [{ pattern: 'test/*.test.js', load: false }],
   testFramework: 'mocha',
   debug: true,
   env: {
     kind: 'chrome',
     params: {
-      runner: '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
+      runner:
+        '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
     },
   },
   postprocessor: wallabyPostprocessor,
diff --git a/packages/testing-helpers/fixture.js b/packages/testing-helpers/fixture.js
index 3d9a21aa..10e58bd1 100644
--- a/packages/testing-helpers/fixture.js
+++ b/packages/testing-helpers/fixture.js
@@ -31,7 +31,7 @@ export function fixtureSync(template, props = {}) {
   parent.innerHTML = template;
   const element = parent.children[0];
   const properties = typeof props === 'function' ? props(element) : props;
-  Object.keys(properties).forEach((prop) => {
+  Object.keys(properties).forEach(prop => {
     element[prop] = properties[prop];
   });
   const wrapper = new FixtureWrapper();
diff --git a/packages/testing-helpers/helpers.js b/packages/testing-helpers/helpers.js
index e8a94331..b8920b90 100644
--- a/packages/testing-helpers/helpers.js
+++ b/packages/testing-helpers/helpers.js
@@ -37,7 +37,7 @@ export function isIE() {
  * @returns {Promise<void>}
  */
 export async function aTimeout(ms) {
-  return new Promise((resolve) => {
+  return new Promise(resolve => {
     setTimeout(resolve, ms);
   });
 }
@@ -76,7 +76,7 @@ export async function triggerFocusFor(element) {
  * @returns {Promise<Event>}
  */
 export async function oneEvent(element, eventName) {
-  return new Promise((resolve) => {
+  return new Promise(resolve => {
     function listener(ev) {
       resolve(ev);
       element.removeEventListener(eventName, listener);
@@ -97,7 +97,7 @@ export async function nextFrame() {
  * @returns {Promise<void>}
  */
 export async function flush() {
-  return new Promise((resolve) => {
+  return new Promise(resolve => {
     if (window.flush) {
       window.flush(() => {
         resolve();
diff --git a/packages/testing-helpers/index.js b/packages/testing-helpers/index.js
index 33dcaca4..a15b2848 100644
--- a/packages/testing-helpers/index.js
+++ b/packages/testing-helpers/index.js
@@ -1,6 +1,12 @@
 export { html, unsafeStatic } from './lit-html.js';
 export {
-  triggerBlurFor, triggerFocusFor, oneEvent, isIE, defineCE, aTimeout, nextFrame,
+  triggerBlurFor,
+  triggerFocusFor,
+  oneEvent,
+  isIE,
+  defineCE,
+  aTimeout,
+  nextFrame,
 } from './helpers.js';
 export { litFixture, litFixtureSync } from './litFixture.js';
 export { fixture, fixtureSync } from './fixture.js';
diff --git a/packages/testing-helpers/karma.conf.js b/packages/testing-helpers/karma.conf.js
index b04473b1..52fa541e 100644
--- a/packages/testing-helpers/karma.conf.js
+++ b/packages/testing-helpers/karma.conf.js
@@ -1,6 +1,6 @@
 const createBaseConfig = require('../testing-karma/create-karma-config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/testing-helpers/karma.es5.bs.config.js b/packages/testing-helpers/karma.es5.bs.config.js
index e22b6893..ad553e4c 100644
--- a/packages/testing-helpers/karma.es5.bs.config.js
+++ b/packages/testing-helpers/karma.es5.bs.config.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma-bs/create-karma-es5-bs.config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/testing-helpers/lit-html.js b/packages/testing-helpers/lit-html.js
index 87db73d1..4c1cf01b 100644
--- a/packages/testing-helpers/lit-html.js
+++ b/packages/testing-helpers/lit-html.js
@@ -28,7 +28,7 @@ export function html(strings, ...values) {
   }
 
   const isDynamicProp = p => p && p.d && typeof p.d === 'string' && Object.keys(p).length === 1;
-  const addToCurrentString = (add) => {
+  const addToCurrentString = add => {
     newStr[newStr.length - 1] = newStr[newStr.length - 1] + add;
   };
 
diff --git a/packages/testing-helpers/wallaby.js b/packages/testing-helpers/wallaby.js
index a99025b2..b0f510a5 100644
--- a/packages/testing-helpers/wallaby.js
+++ b/packages/testing-helpers/wallaby.js
@@ -8,21 +8,15 @@ const wallabyPostprocessor = wallabyWebpack({
 });
 
 module.exports = () => ({
-  files: [
-    '*.js',
-    '!wallaby.js',
-    '!*.config.js',
-    '!*.conf.js',
-  ],
-  tests: [
-    'test/*.test.js',
-  ],
+  files: ['*.js', '!wallaby.js', '!*.config.js', '!*.conf.js'],
+  tests: ['test/*.test.js'],
   testFramework: 'mocha',
   debug: true,
   env: {
     kind: 'chrome',
     params: {
-      runner: '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
+      runner:
+        '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
     },
   },
   postprocessor: wallabyPostprocessor,
diff --git a/packages/testing-karma-bs/create-karma-es5-bs.config.js b/packages/testing-karma-bs/create-karma-es5-bs.config.js
index 1daec2b9..5b620ace 100644
--- a/packages/testing-karma-bs/create-karma-es5-bs.config.js
+++ b/packages/testing-karma-bs/create-karma-es5-bs.config.js
@@ -24,7 +24,7 @@ if (!process.env.BROWSER_STACK_USERNAME || !process.env.BROWSER_STACK_ACCESS_KEY
  *
  * See demo/karma.es5.config.js for an example implementation.
  */
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   return {
diff --git a/packages/testing-karma/create-karma-config.js b/packages/testing-karma/create-karma-config.js
index 1a21b1ea..8df719f5 100644
--- a/packages/testing-karma/create-karma-config.js
+++ b/packages/testing-karma/create-karma-config.js
@@ -6,17 +6,12 @@ const path = require('path');
  * See demo/karma.conf.js for an example implementation.
  */
 module.exports = config => ({
-  browsers: [
-    'ChromeHeadlessNoSandbox',
-  ],
+  browsers: ['ChromeHeadlessNoSandbox'],
 
   customLaunchers: {
     ChromeHeadlessNoSandbox: {
       base: 'ChromeHeadless',
-      flags: [
-        '--no-sandbox',
-        '--disable-setuid-sandbox',
-      ],
+      flags: ['--no-sandbox', '--disable-setuid-sandbox'],
     },
   },
 
diff --git a/packages/testing-karma/create-karma-es5.config.js b/packages/testing-karma/create-karma-es5.config.js
index 03c6f14c..7cadab95 100644
--- a/packages/testing-karma/create-karma-es5.config.js
+++ b/packages/testing-karma/create-karma-es5.config.js
@@ -10,15 +10,21 @@ const createBaseConfig = require('./create-karma-config');
  *
  * See demo/karma.es5.config.js for an example implementation.
  */
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   return {
     ...baseConfig,
     files: [
       { pattern: require.resolve('@babel/polyfill/browser'), watched: false },
-      { pattern: require.resolve('@webcomponents/webcomponentsjs/custom-elements-es5-adapter'), watched: false },
-      { pattern: require.resolve('@webcomponents/webcomponentsjs/webcomponents-bundle'), watched: false },
+      {
+        pattern: require.resolve('@webcomponents/webcomponentsjs/custom-elements-es5-adapter'),
+        watched: false,
+      },
+      {
+        pattern: require.resolve('@webcomponents/webcomponentsjs/webcomponents-bundle'),
+        watched: false,
+      },
     ],
 
     webpack: {
@@ -30,9 +36,7 @@ module.exports = (config) => {
             test: /\.js$/,
             loader: 'babel-loader',
             options: {
-              presets: [
-                ['@babel/preset-env', { targets: 'IE 11' }],
-              ],
+              presets: [['@babel/preset-env', { targets: 'IE 11' }]],
               cacheDirectory: true,
             },
           },
diff --git a/packages/testing/index-no-side-effects.js b/packages/testing/index-no-side-effects.js
index d26b366d..c03d38ed 100644
--- a/packages/testing/index-no-side-effects.js
+++ b/packages/testing/index-no-side-effects.js
@@ -13,9 +13,4 @@ export {
   fixtureSync,
 } from '@open-wc/testing-helpers';
 
-export {
-  chai,
-  expect,
-  should,
-  assert,
-} from '@bundled-es-modules/chai';
+export { chai, expect, should, assert } from '@bundled-es-modules/chai';
diff --git a/packages/testing/index.js b/packages/testing/index.js
index d60d5c56..49dfe2b0 100644
--- a/packages/testing/index.js
+++ b/packages/testing/index.js
@@ -16,9 +16,4 @@ export {
   fixtureSync,
 } from '@open-wc/testing-helpers';
 
-export {
-  chai,
-  expect,
-  should,
-  assert,
-} from '@bundled-es-modules/chai';
+export { chai, expect, should, assert } from '@bundled-es-modules/chai';
diff --git a/packages/testing/karma.conf.js b/packages/testing/karma.conf.js
index 98dd9825..160b9c6c 100644
--- a/packages/testing/karma.conf.js
+++ b/packages/testing/karma.conf.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma/create-karma-config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/testing/karma.es5.bs.config.js b/packages/testing/karma.es5.bs.config.js
index 1ba1c48b..6a9e9159 100644
--- a/packages/testing/karma.es5.bs.config.js
+++ b/packages/testing/karma.es5.bs.config.js
@@ -1,7 +1,7 @@
 // eslint-disable-next-line import/no-extraneous-dependencies
 const createBaseConfig = require('@open-wc/testing-karma-bs/create-karma-es5-bs.config');
 
-module.exports = (config) => {
+module.exports = config => {
   const baseConfig = createBaseConfig(config);
 
   config.set({
diff --git a/packages/testing/register-fixture-cleanup.js b/packages/testing/register-fixture-cleanup.js
index a714d0b8..e7a01060 100644
--- a/packages/testing/register-fixture-cleanup.js
+++ b/packages/testing/register-fixture-cleanup.js
@@ -3,7 +3,7 @@ import { cachedWrappers } from '@open-wc/testing-helpers/fixture.js';
 if (afterEach) {
   afterEach(() => {
     if (cachedWrappers) {
-      cachedWrappers.forEach((wrapper) => {
+      cachedWrappers.forEach(wrapper => {
         document.body.removeChild(wrapper);
       });
     }
diff --git a/packages/testing/wallaby.js b/packages/testing/wallaby.js
index 694b0ed9..2efec33f 100644
--- a/packages/testing/wallaby.js
+++ b/packages/testing/wallaby.js
@@ -5,9 +5,7 @@ const wallabyPostprocessor = wallabyWebpack({
   resolve: {
     modules: [path.resolve(__dirname, 'bower_components'), 'node_modules'],
   },
-  entryPatterns: [
-    'test/index.js',
-  ],
+  entryPatterns: ['test/index.js'],
 });
 
 module.exports = () => ({
@@ -19,15 +17,14 @@ module.exports = () => ({
     { pattern: 'test/index.js', load: false },
     { pattern: 'test/*.test.js', ignore: true },
   ],
-  tests: [
-    { pattern: 'test/*.test.js', load: false },
-  ],
+  tests: [{ pattern: 'test/*.test.js', load: false }],
   testFramework: 'mocha',
   debug: true,
   env: {
     kind: 'chrome',
     params: {
-      runner: '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
+      runner:
+        '--no-sandbox --disable-setuid-sandbox --headless --disable-gpu --disable-translate --disable-extensions --disable-background-networking --safebrowsing-disable-auto-update --disable-sync --metrics-recording-only --disable-default-apps --no-first-run',
     },
   },
   postprocessor: wallabyPostprocessor,
diff --git a/prettier.config.js b/prettier.config.js
new file mode 100644
index 00000000..0ac81de7
--- /dev/null
+++ b/prettier.config.js
@@ -0,0 +1 @@
+module.exports = require('./packages/prettier-config');