diff --git a/.eslintrc.json b/.eslintrc.json
index 1e43a89..5f6c309 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,5 +1,5 @@
 {
-  "extends": "airbnb-base",
+  "extends": ["airbnb-base", "eslint:recommended"],
   "rules": {
     "no-console": "off",
     "import/prefer-default-export": "off"
diff --git a/index.js b/index.js
index 7a6ec83..517a5e0 100644
--- a/index.js
+++ b/index.js
@@ -1,28 +1,8 @@
-import imageResizer from './src/imageResizer';
 import url from 'url';
+import imageResizer from './src/imageResizer';
 
-export const handle = (event, context, callback) => {
-  console.log('eventObject: %s', JSON.stringify(event, null, 2));
-  console.log('context: %s', JSON.stringify(context, null, 2));
-
-  const image = sourceImage(event);
-
-  imageResizer({sourceBucket: image.bucket, sourceKey: image.key, options: image.options})
-    .then(data => callback(null, successResponse(data)))
-    .catch(err => callback(err));
-};
-
-const successResponse = (data) => {
-  // NOTE: lambda proxy integration format
-  return {
-    isBase64Encoded: false,
-    statusCode: 201,
-    headers: {
-      "Content-Type": 'application/json'
-    },
-    body: JSON.stringify(data),
-  };
-};
+const isS3Event = event => typeof event.Records === 'object';
+const isApiGatewayEvent = event => typeof event.Records === 'undefined';
 
 const sourceImage = (event) => {
   let bucket = '';
@@ -38,7 +18,7 @@ const sourceImage = (event) => {
   if (isApiGatewayEvent(event)) {
     const u = url.parse(event.queryStringParameters.source_url);
     bucket = u.hostname;
-    key = u.path.replace(/^\//, "");
+    key = u.path.replace(/^\//, '');
     options = {
       resizeOption: event.queryStringParameters.resize_option,
       destS3Bucket: event.queryStringParameters.dest_s3_bucket,
@@ -46,13 +26,27 @@ const sourceImage = (event) => {
     };
   }
 
-  return { bucket: bucket, key: key, options: options };
+  return { bucket, key, options };
 };
 
-const isS3Event = (event) => {
-  return typeof event.Records === 'object';
-};
+const successResponse = data =>
+  // NOTE: lambda proxy integration format
+   ({
+     isBase64Encoded: false,
+     statusCode: 201,
+     headers: {
+       'Content-Type': 'application/json',
+     },
+     body: JSON.stringify(data),
+   });
+
+export const handle = (event, context, callback) => {
+  console.log('eventObject: %s', JSON.stringify(event, null, 2));
+  console.log('context: %s', JSON.stringify(context, null, 2));
+
+  const image = sourceImage(event);
 
-const isApiGatewayEvent = (event) => {
-  return typeof event.Records === 'undefined';
+  imageResizer({ sourceBucket: image.bucket, sourceKey: image.key, options: image.options })
+    .then(data => callback(null, successResponse(data)))
+    .catch(err => callback(err));
 };
diff --git a/src/imageResizer.js b/src/imageResizer.js
index 40af2b9..aa870d4 100644
--- a/src/imageResizer.js
+++ b/src/imageResizer.js
@@ -37,7 +37,7 @@ const resizeImage = (imagePath, info, options) =>
    new Promise((resolve, reject) => {
      console.log('resizeImage start...');
      const resizeOpts = /^(\d+)x(\d+)([%@!<>])?$/g.exec(
-       options.resizeOption || process.env.RESIZE_OPTION
+       options.resizeOption || process.env.RESIZE_OPTION,
      );
 
      gm(imagePath)
@@ -64,7 +64,7 @@ const uploadImage = (buffer, info, options) =>
    })
 ;
 
-export default async ({sourceBucket, sourceKey, options}) => {
+export default async ({ sourceBucket, sourceKey, options }) => {
   const imagePath = await downloadImage({
     Bucket: sourceBucket,
     Key: sourceKey,
diff --git a/yarn.lock b/yarn.lock
index 24cb8c1..5755b3f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -45,10 +45,14 @@ acorn@^4.0.3:
   version "4.0.13"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-4.0.13.tgz#105495ae5361d697bd195c825192e1ad7f253787"
 
-acorn@^5.0.0, acorn@^5.1.1:
+acorn@^5.0.0:
   version "5.1.1"
   resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.1.1.tgz#53fe161111f912ab999ee887a90a0bc52822fd75"
 
+acorn@^5.2.1:
+  version "5.2.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-5.2.1.tgz#317ac7821826c22c702d66189ab8359675f135d7"
+
 agent-base@2:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/agent-base/-/agent-base-2.1.1.tgz#d6de10d5af6132d5bd692427d46fc538539094c7"
@@ -283,7 +287,15 @@ aws4@^1.2.1:
   version "1.6.0"
   resolved "https://registry.yarnpkg.com/aws4/-/aws4-1.6.0.tgz#83ef5ca860b2b32e4a0deedee8c771b9db57471e"
 
-babel-code-frame@^6.16.0, babel-code-frame@^6.22.0:
+babel-code-frame@^6.16.0:
+  version "6.26.0"
+  resolved "https://registry.yarnpkg.com/babel-code-frame/-/babel-code-frame-6.26.0.tgz#63fd43f7dc1e3bb7ce35947db8fe369a3f58c74b"
+  dependencies:
+    chalk "^1.1.3"
+    esutils "^2.0.2"
+    js-tokens "^3.0.2"
+
+babel-code-frame@^6.22.0:
   version "6.22.0"
   resolved "https://registry.yarnpkg.com/babel-code-frame/-/babel-code-frame-6.22.0.tgz#027620bee567a88c32561574e7fd0801d33118e4"
   dependencies:
@@ -1055,8 +1067,8 @@ cli-cursor@^1.0.1:
     restore-cursor "^1.0.1"
 
 cli-width@^2.0.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/cli-width/-/cli-width-2.1.0.tgz#b234ca209b29ef66fc518d9b98d5847b00edf00a"
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/cli-width/-/cli-width-2.2.0.tgz#ff19ede8a9a5e579324147b0c11f0fbcbabed639"
 
 cliui@^2.1.0:
   version "2.1.0"
@@ -1286,7 +1298,7 @@ date-now@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/date-now/-/date-now-0.1.4.tgz#eaf439fd4d4848ad74e5cc7dbef200672b9e345b"
 
-debug@2, debug@2.6.8, debug@^2.2.0, debug@^2.6.8:
+debug@2, debug@2.6.8, debug@^2.2.0:
   version "2.6.8"
   resolved "https://registry.yarnpkg.com/debug/-/debug-2.6.8.tgz#e731531ca2ede27d188222427da17821d68ff4fc"
   dependencies:
@@ -1298,7 +1310,13 @@ debug@2.6.7:
   dependencies:
     ms "2.0.0"
 
-debug@^2.1.1, debug@~2.2.0:
+debug@^2.1.1, debug@^2.6.8:
+  version "2.6.9"
+  resolved "https://registry.yarnpkg.com/debug/-/debug-2.6.9.tgz#5d128515df134ff327e90a4c93f4e077a536341f"
+  dependencies:
+    ms "2.0.0"
+
+debug@~2.2.0:
   version "2.2.0"
   resolved "https://registry.yarnpkg.com/debug/-/debug-2.2.0.tgz#f87057e995b1a1f6ae6a4960664137bc56f039da"
   dependencies:
@@ -1426,11 +1444,10 @@ doctrine@1.5.0:
     isarray "^1.0.0"
 
 doctrine@^2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/doctrine/-/doctrine-2.0.0.tgz#c73d8d2909d22291e1a007a395804da8b665fe63"
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/doctrine/-/doctrine-2.0.2.tgz#68f96ce8efc56cc42651f1faadb4f175273b0075"
   dependencies:
     esutils "^2.0.2"
-    isarray "^1.0.0"
 
 dom-walk@^0.1.0:
   version "0.1.1"
@@ -1519,20 +1536,20 @@ error-ex@^1.2.0:
   dependencies:
     is-arrayish "^0.2.1"
 
-es5-ext@^0.10.14, es5-ext@^0.10.9, es5-ext@~0.10.14:
-  version "0.10.26"
-  resolved "https://registry.yarnpkg.com/es5-ext/-/es5-ext-0.10.26.tgz#51b2128a531b70c4f6764093a73cbebb82186372"
+es5-ext@^0.10.14, es5-ext@^0.10.35, es5-ext@^0.10.9, es5-ext@~0.10.14:
+  version "0.10.37"
+  resolved "https://registry.yarnpkg.com/es5-ext/-/es5-ext-0.10.37.tgz#0ee741d148b80069ba27d020393756af257defc3"
   dependencies:
-    es6-iterator "2"
-    es6-symbol "~3.1"
+    es6-iterator "~2.0.1"
+    es6-symbol "~3.1.1"
 
-es6-iterator@2, es6-iterator@^2.0.1, es6-iterator@~2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/es6-iterator/-/es6-iterator-2.0.1.tgz#8e319c9f0453bf575d374940a655920e59ca5512"
+es6-iterator@^2.0.1, es6-iterator@~2.0.1:
+  version "2.0.3"
+  resolved "https://registry.yarnpkg.com/es6-iterator/-/es6-iterator-2.0.3.tgz#a7de889141a05a94b0854403b2d0a0fbfa98f3b7"
   dependencies:
     d "1"
-    es5-ext "^0.10.14"
-    es6-symbol "^3.1"
+    es5-ext "^0.10.35"
+    es6-symbol "^3.1.1"
 
 es6-map@^0.1.3:
   version "0.1.5"
@@ -1555,7 +1572,7 @@ es6-set@~0.1.5:
     es6-symbol "3.1.1"
     event-emitter "~0.3.5"
 
-es6-symbol@3.1.1, es6-symbol@^3.1, es6-symbol@^3.1.1, es6-symbol@~3.1, es6-symbol@~3.1.1:
+es6-symbol@3.1.1, es6-symbol@^3.1.1, es6-symbol@~3.1.1:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/es6-symbol/-/es6-symbol-3.1.1.tgz#bf00ef4fdab6ba1b46ecb7b629b4c7ed5715cc77"
   dependencies:
@@ -1607,8 +1624,8 @@ eslint-module-utils@^2.1.1:
     pkg-dir "^1.0.0"
 
 eslint-plugin-import@^2.2.0:
-  version "2.7.0"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.7.0.tgz#21de33380b9efb55f5ef6d2e210ec0e07e7fa69f"
+  version "2.8.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-import/-/eslint-plugin-import-2.8.0.tgz#fa1b6ef31fcb3c501c09859c1b86f1fc5b986894"
   dependencies:
     builtin-modules "^1.1.1"
     contains-path "^0.1.0"
@@ -1662,10 +1679,10 @@ eslint@^3.9.1:
     user-home "^2.0.0"
 
 espree@^3.4.0:
-  version "3.5.0"
-  resolved "https://registry.yarnpkg.com/espree/-/espree-3.5.0.tgz#98358625bdd055861ea27e2867ea729faf463d8d"
+  version "3.5.2"
+  resolved "https://registry.yarnpkg.com/espree/-/espree-3.5.2.tgz#756ada8b979e9dcfcdb30aad8d1a9304a905e1ca"
   dependencies:
-    acorn "^5.1.1"
+    acorn "^5.2.1"
     acorn-jsx "^3.0.0"
 
 esprima@^4.0.0:
@@ -1881,8 +1898,8 @@ find-up@^2.0.0:
     locate-path "^2.0.0"
 
 flat-cache@^1.2.1:
-  version "1.2.2"
-  resolved "https://registry.yarnpkg.com/flat-cache/-/flat-cache-1.2.2.tgz#fa86714e72c21db88601761ecf2f555d1abc6b96"
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/flat-cache/-/flat-cache-1.3.0.tgz#d3030b32b38154f4e3b7e9c709f490f7ef97c481"
   dependencies:
     circular-json "^0.3.1"
     del "^2.0.2"
@@ -1970,8 +1987,8 @@ fstream@^1.0.0, fstream@^1.0.10, fstream@^1.0.2:
     rimraf "2"
 
 function-bind@^1.0.2:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.0.tgz#16176714c801798e4e8f2cf7f7529467bb4a5771"
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.1.tgz#a56899d3ea3c9bab874bb9773b7c5ede92f4895d"
 
 gauge@~1.2.5:
   version "1.2.7"
@@ -2274,8 +2291,8 @@ ieee754@^1.1.4:
   resolved "https://registry.yarnpkg.com/ieee754/-/ieee754-1.1.8.tgz#be33d40ac10ef1926701f6f08a2d86fbfd1ad3e4"
 
 ignore@^3.2.0:
-  version "3.3.3"
-  resolved "https://registry.yarnpkg.com/ignore/-/ignore-3.3.3.tgz#432352e57accd87ab3110e82d3fea0e47812156d"
+  version "3.3.7"
+  resolved "https://registry.yarnpkg.com/ignore/-/ignore-3.3.7.tgz#612289bfb3c220e186a58118618d5be8c1bab021"
 
 imurmurhash@^0.1.4:
   version "0.1.4"
@@ -2342,8 +2359,8 @@ inquirer@^1.0.2:
     through "^2.3.6"
 
 interpret@^1.0.0:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/interpret/-/interpret-1.0.3.tgz#cbc35c62eeee73f19ab7b10a801511401afc0f90"
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/interpret/-/interpret-1.1.0.tgz#7ed1b1410c6a0e0f78cf95d3b8440c63f78b8614"
 
 invariant@^2.2.0:
   version "2.2.2"
@@ -2420,8 +2437,8 @@ is-glob@^2.0.0, is-glob@^2.0.1:
     is-extglob "^1.0.0"
 
 is-my-json-valid@^2.10.0:
-  version "2.16.0"
-  resolved "https://registry.yarnpkg.com/is-my-json-valid/-/is-my-json-valid-2.16.0.tgz#f079dd9bfdae65ee2038aae8acbc86ab109e3693"
+  version "2.17.1"
+  resolved "https://registry.yarnpkg.com/is-my-json-valid/-/is-my-json-valid-2.17.1.tgz#3da98914a70a22f0a8563ef1511a246c6fc55471"
   dependencies:
     generate-function "^2.0.0"
     generate-object-property "^1.1.0"
@@ -2459,8 +2476,8 @@ is-path-in-cwd@^1.0.0:
     is-path-inside "^1.0.0"
 
 is-path-inside@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/is-path-inside/-/is-path-inside-1.0.0.tgz#fc06e5a1683fbda13de667aff717bbc10a48f37f"
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/is-path-inside/-/is-path-inside-1.0.1.tgz#8ef5b7de50437a3fdca6b4e865ef7aa55cb48036"
   dependencies:
     path-is-inside "^1.0.1"
 
@@ -2485,10 +2502,8 @@ is-redirect@^1.0.0:
   resolved "https://registry.yarnpkg.com/is-redirect/-/is-redirect-1.0.0.tgz#1d03dded53bd8db0f30c26e4f95d36fc7c87dc24"
 
 is-resolvable@^1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/is-resolvable/-/is-resolvable-1.0.0.tgz#8df57c61ea2e3c501408d100fb013cf8d6e0cc62"
-  dependencies:
-    tryit "^1.0.1"
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/is-resolvable/-/is-resolvable-1.0.1.tgz#acca1cd36dbe44b974b924321555a70ba03b1cf4"
 
 is-retry-allowed@^1.0.0:
   version "1.1.0"
@@ -2543,11 +2558,18 @@ jmespath@0.15.0:
   version "0.15.0"
   resolved "https://registry.yarnpkg.com/jmespath/-/jmespath-0.15.0.tgz#a3f222a9aae9f966f5d27c796510e28091764217"
 
-js-tokens@^3.0.0:
+js-tokens@^3.0.0, js-tokens@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-3.0.2.tgz#9866df395102130e38f7f996bceb65443209c25b"
 
-js-yaml@^3.5.1, js-yaml@^3.6.1, js-yaml@^3.8.3:
+js-yaml@^3.5.1:
+  version "3.10.0"
+  resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.10.0.tgz#2e78441646bd4682e963f22b6e92823c309c62dc"
+  dependencies:
+    argparse "^1.0.7"
+    esprima "^4.0.0"
+
+js-yaml@^3.6.1, js-yaml@^3.8.3:
   version "3.9.1"
   resolved "https://registry.yarnpkg.com/js-yaml/-/js-yaml-3.9.1.tgz#08775cebdfdd359209f0d2acd383c8f86a6904a0"
   dependencies:
@@ -3541,8 +3563,8 @@ resolve-from@^1.0.0:
   resolved "https://registry.yarnpkg.com/resolve-from/-/resolve-from-1.0.1.tgz#26cbfe935d1aeeeabb29bc3fe5aeb01e93d44226"
 
 resolve@^1.1.6, resolve@^1.2.0:
-  version "1.4.0"
-  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.4.0.tgz#a75be01c53da25d934a98ebd0e4c4a7312f92a86"
+  version "1.5.0"
+  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.5.0.tgz#1f09acce796c9a762579f31b2c1cc4c3cddf9f36"
   dependencies:
     path-parse "^1.0.5"
 
@@ -3559,12 +3581,18 @@ right-align@^0.1.1:
   dependencies:
     align-text "^0.1.1"
 
-rimraf@2, rimraf@^2.2.8, rimraf@^2.5.1, rimraf@^2.6.1:
+rimraf@2, rimraf@^2.5.1, rimraf@^2.6.1:
   version "2.6.1"
   resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.6.1.tgz#c2338ec643df7a1b7fe5c54fa86f57428a55f33d"
   dependencies:
     glob "^7.0.5"
 
+rimraf@^2.2.8:
+  version "2.6.2"
+  resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.6.2.tgz#2ed8150d24a16ea8651e6d6ef0f47c4158ce7a36"
+  dependencies:
+    glob "^7.0.5"
+
 ripemd160@^2.0.0, ripemd160@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/ripemd160/-/ripemd160-2.0.1.tgz#0f4584295c53a3628af7e6d79aca21ce57d1c6e7"
@@ -4042,10 +4070,6 @@ trim-right@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/trim-right/-/trim-right-1.0.1.tgz#cb2e1203067e0c8de1f614094b9fe45704ea6003"
 
-tryit@^1.0.1:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/tryit/-/tryit-1.0.3.tgz#393be730a9446fd1ead6da59a014308f36c289cb"
-
 ts-node@^3.2.0:
   version "3.3.0"
   resolved "https://registry.yarnpkg.com/ts-node/-/ts-node-3.3.0.tgz#c13c6a3024e30be1180dd53038fc209289d4bf69"