diff --git a/index.js b/index.js
index ca618672..621ea9db 100644
--- a/index.js
+++ b/index.js
@@ -48,7 +48,7 @@ async function run(options, plugins) {
 
   options.repositoryUrl = await getGitAuthUrl(options);
 
-  if (!await isBranchUpToDate(options.branch)) {
+  if (!(await isBranchUpToDate(options.branch))) {
     logger.log(
       "The local branch %s is behind the remote one, therefore a new version won't be published.",
       options.branch
diff --git a/lib/get-last-release.js b/lib/get-last-release.js
index 9c65588e..1d8fdecf 100644
--- a/lib/get-last-release.js
+++ b/lib/get-last-release.js
@@ -20,6 +20,7 @@ const {gitTags, isRefInHistory, gitTagHead} = require('./git');
  * - Sort the versions
  * - Retrive the highest version
  *
+ * @param {String} tagFormat Git tag format.
  * @param {Object} logger Global logger.
  * @return {Promise<LastRelease>} The last tagged release or `undefined` if none is found.
  */
diff --git a/lib/plugins/normalize.js b/lib/plugins/normalize.js
index bf71bffa..42c55226 100644
--- a/lib/plugins/normalize.js
+++ b/lib/plugins/normalize.js
@@ -37,21 +37,20 @@ module.exports = (pluginType, pluginsPath, globalOpts, pluginOpts, logger) => {
     throw getError('EPLUGIN', {pluginType, pluginName});
   }
 
-  return Object.defineProperty(
-    async input => {
-      const definition = PLUGINS_DEFINITIONS[pluginType];
-      try {
-        const result = await func(cloneDeep(input));
-        if (definition && definition.output && !definition.output.validator(result)) {
-          throw getError(PLUGINS_DEFINITIONS[pluginType].output.error, {result, pluginName});
-        }
-        return result;
-      } catch (err) {
-        extractErrors(err).forEach(err => Object.assign(err, {pluginName}));
-        throw err;
+  const validator = async input => {
+    const definition = PLUGINS_DEFINITIONS[pluginType];
+    try {
+      const result = await func(cloneDeep(input));
+      if (definition && definition.output && !definition.output.validator(result)) {
+        throw getError(PLUGINS_DEFINITIONS[pluginType].output.error, {result, pluginName});
       }
-    },
-    'pluginName',
-    {value: pluginName, writable: false, enumerable: true}
-  );
+      return result;
+    } catch (err) {
+      extractErrors(err).forEach(err => Object.assign(err, {pluginName}));
+      throw err;
+    }
+  };
+
+  Reflect.defineProperty(validator, 'pluginName', {value: pluginName, writable: false, enumerable: true});
+  return validator;
 };
diff --git a/lib/verify.js b/lib/verify.js
index 2704d10c..5015ed9d 100644
--- a/lib/verify.js
+++ b/lib/verify.js
@@ -6,14 +6,14 @@ const getError = require('./get-error');
 module.exports = async options => {
   const errors = [];
 
-  if (!await isGitRepo()) {
+  if (!(await isGitRepo())) {
     errors.push(getError('ENOGITREPO'));
   } else if (!options.repositoryUrl) {
     errors.push(getError('ENOREPOURL'));
   }
 
   // Verify that compiling the `tagFormat` produce a valid Git tag
-  if (!await verifyTagName(template(options.tagFormat)({version: '0.0.0'}))) {
+  if (!(await verifyTagName(template(options.tagFormat)({version: '0.0.0'})))) {
     errors.push(getError('EINVALIDTAGFORMAT', {tagFormat: options.tagFormat}));
   }
 
diff --git a/package.json b/package.json
index 8a1e7885..4d8ea896 100644
--- a/package.json
+++ b/package.json
@@ -64,7 +64,7 @@
     "proxyquire": "^2.0.0",
     "sinon": "^5.0.1",
     "tempy": "^0.2.1",
-    "xo": "^0.20.0"
+    "xo": "^0.21.0"
   },
   "engines": {
     "node": ">=8.3"
@@ -104,7 +104,8 @@
     "all": true
   },
   "prettier": {
-    "printWidth": 120
+    "printWidth": 120,
+    "trailingComma": "es5"
   },
   "publishConfig": {
     "tag": "next"
diff --git a/test/cli.test.js b/test/cli.test.js
index b03b145e..6946fe8a 100644
--- a/test/cli.test.js
+++ b/test/cli.test.js
@@ -165,12 +165,12 @@ test.serial('Do not set properties in option for which arg is not in command lin
 
   await cli();
 
-  t.false(Object.prototype.hasOwnProperty.call(run.args[0][0], 'ci'));
-  t.false(Object.prototype.hasOwnProperty.call(run.args[0][0], 'd'));
-  t.false(Object.prototype.hasOwnProperty.call(run.args[0][0], 'dry-run'));
-  t.false(Object.prototype.hasOwnProperty.call(run.args[0][0], 'debug'));
-  t.false(Object.prototype.hasOwnProperty.call(run.args[0][0], 'r'));
-  t.false(Object.prototype.hasOwnProperty.call(run.args[0][0], 't'));
+  t.false(Reflect.apply(Object.prototype.hasOwnProperty, run.args[0][0], ['ci']));
+  t.false(Reflect.apply(Object.prototype.hasOwnProperty, run.args[0][0], ['d']));
+  t.false(Reflect.apply(Object.prototype.hasOwnProperty, run.args[0][0], ['dry-run']));
+  t.false(Reflect.apply(Object.prototype.hasOwnProperty, run.args[0][0], ['debug']));
+  t.false(Reflect.apply(Object.prototype.hasOwnProperty, run.args[0][0], ['r']));
+  t.false(Reflect.apply(Object.prototype.hasOwnProperty, run.args[0][0], ['t']));
 });
 
 test.serial('Set "noCi" options to "true" with "--no-ci"', async t => {
diff --git a/test/helpers/git-utils.js b/test/helpers/git-utils.js
index 6e496ddc..f80a2584 100644
--- a/test/helpers/git-utils.js
+++ b/test/helpers/git-utils.js
@@ -20,7 +20,7 @@ import getStream from 'get-stream';
  * If `withRemote` is `false`, creates a regular repository and initialize it. Change the current working directory to the repository root.
  *
  * @param {Boolean} withRemote `true` to create a shallow clone of a bare repository.
- * @param {String} [branc='master'] The branch to initialize.
+ * @param {String} [branch='master'] The branch to initialize.
  * @return {String} The path of the clone if `withRemote` is `true`, the path of the repository otherwise.
  */
 export async function gitRepo(withRemote, branch = 'master') {
diff --git a/test/helpers/gitbox.js b/test/helpers/gitbox.js
index 9f09e865..76c40ad0 100644
--- a/test/helpers/gitbox.js
+++ b/test/helpers/gitbox.js
@@ -16,8 +16,6 @@ const gitCredential = `${GIT_USERNAME}:${GIT_PASSWORD}`;
 
 /**
  * Download the `gitbox` Docker image, create a new container and start it.
- *
- * @return {Promise} Promise that resolves when the container is started.
  */
 async function start() {
   await getStream(await docker.pull(IMAGE));
@@ -39,8 +37,6 @@ async function start() {
 
 /**
  * Stop and remote the `mockserver` Docker container.
- *
- * @return {Promise} Promise that resolves when the container is stopped.
  */
 async function stop() {
   await container.stop();
diff --git a/test/helpers/mockserver.js b/test/helpers/mockserver.js
index 4e8f0bfa..d9c28e96 100644
--- a/test/helpers/mockserver.js
+++ b/test/helpers/mockserver.js
@@ -12,8 +12,6 @@ let container;
 
 /**
  * Download the `mockserver` Docker image, create a new container and start it.
- *
- * @return {Promise} Promise that resolves when the container is started.
  */
 async function start() {
   await getStream(await docker.pull(IMAGE));
@@ -39,8 +37,6 @@ async function start() {
 
 /**
  * Stop and remote the `mockserver` Docker container.
- *
- * @return {Promise} Promise that resolves when the container is stopped.
  */
 async function stop() {
   await container.stop();
diff --git a/test/helpers/npm-registry.js b/test/helpers/npm-registry.js
index 00309f00..405c35fd 100644
--- a/test/helpers/npm-registry.js
+++ b/test/helpers/npm-registry.js
@@ -16,8 +16,6 @@ let container;
 
 /**
  * Download the `npm-docker-couchdb` Docker image, create a new container and start it.
- *
- * @return {Promise} Promise that resolves when the container is started.
  */
 async function start() {
   await getStream(await docker.pull(IMAGE));
@@ -69,8 +67,6 @@ const authEnv = {
 
 /**
  * Stop and remote the `npm-docker-couchdb` Docker container.
- *
- * @return {Promise} Promise that resolves when the container is stopped.
  */
 async function stop() {
   await container.stop();