diff --git a/src/api/endpoint/api/publish.js b/src/api/endpoint/api/publish.js
index 5834e4942..a71681269 100644
--- a/src/api/endpoint/api/publish.js
+++ b/src/api/endpoint/api/publish.js
@@ -5,7 +5,7 @@ import Path from 'path';
 import mime from 'mime';
 
 import {API_MESSAGE, HEADERS} from '../../../lib/constants';
-import {DIST_TAGS, validate_metadata, isObject, ErrorCode} from '../../../lib/utils';
+import {DIST_TAGS, validateMetadata, isObject, ErrorCode} from '../../../lib/utils';
 import {media, expectJson, allow} from '../../middleware';
 import {notify} from '../../../lib/notify';
 
@@ -112,7 +112,7 @@ export default function(router: Router, auth: IAuth, storage: IStorageHandler, c
     }
 
     try {
-      metadata = validate_metadata(req.body, name);
+      metadata = validateMetadata(req.body, name);
     } catch (err) {
       return next(ErrorCode.getBadData('bad incoming package data'));
     }
diff --git a/src/api/middleware.js b/src/api/middleware.js
index 2d2eef1fc..6521dec36 100644
--- a/src/api/middleware.js
+++ b/src/api/middleware.js
@@ -3,7 +3,7 @@
 import _ from 'lodash';
 import {
   validateName as utilValidateName,
-  validate_package as utilValidatePackage,
+  validatePackage as utilValidatePackage,
   isObject,
   ErrorCode} from '../lib/utils';
 import {API_ERROR, HEADER_TYPE, HEADERS, HTTP_STATUS, TOKEN_BASIC, TOKEN_BEARER} from '../lib/constants';
diff --git a/src/lib/bootstrap.js b/src/lib/bootstrap.js
index 76784e803..98329ea5b 100644
--- a/src/lib/bootstrap.js
+++ b/src/lib/bootstrap.js
@@ -9,7 +9,7 @@ import https from 'https';
 // $FlowFixMe
 import constants from 'constants';
 import endPointAPI from '../api/index';
-import {parse_address} from './utils';
+import {parseAddress} from './utils';
 
 import type {Callback} from '@verdaccio/types';
 import type {$Application} from 'express';
@@ -41,7 +41,7 @@ export function getListListenAddresses(argListen: string, configListen: mixed) {
     addresses = [DEFAULT_PORT];
   }
   addresses = addresses.map(function(addr) {
-    const parsedAddr = parse_address(addr);
+    const parsedAddr = parseAddress(addr);
 
     if (!parsedAddr) {
       logger.logger.warn({addr: addr},
diff --git a/src/lib/config-path.js b/src/lib/config-path.js
index 258bb8c88..6a12e0a0e 100644
--- a/src/lib/config-path.js
+++ b/src/lib/config-path.js
@@ -6,7 +6,7 @@ import Path from 'path';
 import logger from './logger';
 import mkdirp from 'mkdirp';
 
-import {folder_exists, fileExists} from './utils';
+import {folderExists, fileExists} from './utils';
 
 const CONFIG_FILE = 'config.yaml';
 const XDG = 'xdg';
@@ -65,7 +65,7 @@ function updateStorageLinks(configLocation, defaultConfig) {
     // If $XDG_DATA_HOME is either not set or empty, a default equal to $HOME/.local/share should be used.
     // $FlowFixMe
     let dataDir = process.env.XDG_DATA_HOME || Path.join(process.env.HOME, '.local', 'share');
-    if (folder_exists(dataDir)) {
+    if (folderExists(dataDir)) {
       dataDir = Path.resolve(Path.join(dataDir, pkgJSON.name, 'storage'));
       return defaultConfig.replace(/^storage: .\/storage$/m, `storage: ${dataDir}`);
     } else {
@@ -81,7 +81,7 @@ const getXDGDirectory = () => {
   const XDGConfig = getXDGHome() ||
         process.env.HOME && Path.join(process.env.HOME, '.config');
 
-  if (XDGConfig && folder_exists(XDGConfig)) {
+  if (XDGConfig && folderExists(XDGConfig)) {
     return {
       path: Path.join(XDGConfig, pkgJSON.name, CONFIG_FILE),
       type: XDG,
@@ -92,7 +92,7 @@ const getXDGDirectory = () => {
 const getXDGHome = () => process.env.XDG_CONFIG_HOME;
 
 const getWindowsDirectory = () => {
-  if (process.platform === WIN32 && process.env.APPDATA && folder_exists(process.env.APPDATA)) {
+  if (process.platform === WIN32 && process.env.APPDATA && folderExists(process.env.APPDATA)) {
     return {
       path: Path.resolve(Path.join(process.env.APPDATA, pkgJSON.name, CONFIG_FILE)),
       type: WIN,
diff --git a/src/lib/constants.js b/src/lib/constants.js
index ea367f7e9..19474ef82 100644
--- a/src/lib/constants.js
+++ b/src/lib/constants.js
@@ -13,6 +13,10 @@ export const HEADERS = {
   GZIP: 'gzip',
 };
 
+export const CHARACTER_ENCODING = {
+  UTF8: 'utf-8'
+}
+
 export const HEADER_TYPE = {
   CONTENT_ENCODING: 'content-encoding',
   CONTENT_TYPE: 'content-type',
diff --git a/src/lib/storage.js b/src/lib/storage.js
index fdbe3b6ac..c15c2b9ab 100644
--- a/src/lib/storage.js
+++ b/src/lib/storage.js
@@ -13,7 +13,7 @@ import {checkPackageLocal, publishPackage, checkPackageRemote, cleanUpLinksRef,
 mergeUplinkTimeIntoLocal, generatePackageTemplate} from './storage-utils';
 import {setupUpLinks, updateVersionsHiddenUpLink} from './uplink-util';
 import {mergeVersions} from './metadata-utils';
-import {ErrorCode, normalizeDistTags, validate_metadata, isObject, DIST_TAGS} from './utils';
+import {ErrorCode, normalizeDistTags, validateMetadata, isObject, DIST_TAGS} from './utils';
 import type {IStorage, IProxy, IStorageHandler, ProxyList, StringValue} from '../../types';
 import type {
 Versions,
@@ -444,7 +444,7 @@ class Storage implements IStorageHandler {
         }
 
         try {
-          validate_metadata(upLinkResponse, name);
+          validateMetadata(upLinkResponse, name);
         } catch (err) {
           self.logger.error({
             sub: 'out',
diff --git a/src/lib/utils.js b/src/lib/utils.js
index 9231d08ce..5da764f9d 100644
--- a/src/lib/utils.js
+++ b/src/lib/utils.js
@@ -1,4 +1,5 @@
 // @flow
+// @prettier
 import _ from 'lodash';
 import fs from 'fs';
 import assert from 'assert';
@@ -13,6 +14,7 @@ import {
   API_ERROR,
   DEFAULT_PORT,
   DEFAULT_DOMAIN,
+  CHARACTER_ENCODING
 } from './constants';
 import {generateGravatarUrl} from '../utils/user';
 
@@ -41,17 +43,17 @@ export function convertPayloadToBase64(payload: string): Buffer {
  * Validate a package.
  * @return {Boolean} whether the package is valid or not
  */
-function validate_package(name: any): boolean {
-  name = name.split('/', 2);
-  if (name.length === 1) {
+export function validatePackage(name: string): boolean {
+  const nameList = name.split('/', 2);
+  if (nameList.length === 1) {
     // normal package
-    return validateName(name[0]);
+    return validateName(nameList[0]);
   } else {
     // scoped package
     return (
-      name[0][0] === '@' &&
-      validateName(name[0].slice(1)) &&
-      validateName(name[1])
+      nameList[0][0] === '@' &&
+      validateName(nameList[0].slice(1)) &&
+      validateName(nameList[1])
     );
   }
 }
@@ -61,7 +63,7 @@ function validate_package(name: any): boolean {
  * @param {*} name  the package name
  * @return {Boolean} whether is valid or not
  */
-function validateName(name: string): boolean {
+export function validateName(name: string): boolean {
   if (_.isString(name) === false) {
     return false;
   }
@@ -84,7 +86,7 @@ function validateName(name: string): boolean {
  * @param {*} obj the element
  * @return {Boolean}
  */
-function isObject(obj: any): boolean {
+export function isObject(obj: any): boolean {
   return _.isObject(obj) && _.isNull(obj) === false && _.isArray(obj) === false;
 }
 
@@ -95,7 +97,7 @@ function isObject(obj: any): boolean {
  * @param {*} name
  * @return {Object} the object with additional properties as dist-tags ad versions
  */
-function validate_metadata(object: Package, name: string) {
+export function validateMetadata(object: Package, name: string): Object {
   assert(isObject(object), 'not a json object');
   assert.equal(object.name, name);
 
@@ -118,7 +120,7 @@ function validate_metadata(object: Package, name: string) {
  * Create base url for registry.
  * @return {String} base registry url
  */
-function combineBaseUrl(
+export function combineBaseUrl(
   protocol: string,
   host: string,
   prefix?: string
@@ -204,15 +206,11 @@ export function getLocalRegistryTarballUri(
  * @param {*} tag
  * @return {Boolean} whether a package has been tagged
  */
-function tagVersion(data: Package, version: string, tag: StringValue) {
-  if (tag) {
-    if (data[DIST_TAGS][tag] !== version) {
-      if (semver.parse(version, true)) {
-        // valid version - store
-        data[DIST_TAGS][tag] = version;
-        return true;
-      }
-    }
+export function tagVersion(data: Package, version: string, tag: StringValue): boolean {
+  if (tag && data[DIST_TAGS][tag] !== version && semver.parse(version, true)) {
+    // valid version - store
+    data[DIST_TAGS][tag] = version;
+    return true;
   }
   return false;
 }
@@ -221,7 +219,7 @@ function tagVersion(data: Package, version: string, tag: StringValue) {
  * Gets version from a package object taking into account semver weirdness.
  * @return {String} return the semantic version of a package
  */
-function getVersion(pkg: Package, version: any) {
+export function getVersion(pkg: Package, version: any) {
   // this condition must allow cast
   if (pkg.versions[version] != null) {
     return pkg.versions[version];
@@ -254,7 +252,7 @@ function getVersion(pkg: Package, version: any) {
  * @param {*} urlAddress the internet address definition
  * @return {Object|Null} literal object that represent the address parsed
  */
-function parse_address(urlAddress: any) {
+export function parseAddress(urlAddress: any) {
   //
   // TODO: refactor it to something more reasonable?
   //
@@ -287,7 +285,7 @@ function parse_address(urlAddress: any) {
  * Function filters out bad semver versions and sorts the array.
  * @return {Array} sorted Array
  */
-function semverSort(listVersions: Array<string>): string[] {
+export function semverSort(listVersions: Array<string>): string[] {
   return listVersions
     .filter(function(x) {
       if (!semver.parse(x, true)) {
@@ -353,7 +351,7 @@ const parseIntervalTable = {
  * @param {*} interval
  * @return {Number}
  */
-function parseInterval(interval: any) {
+export function parseInterval(interval: any): number {
   if (typeof interval === 'number') {
     return interval * 1000;
   }
@@ -380,16 +378,16 @@ function parseInterval(interval: any) {
  * @param {*} req
  * @return {String}
  */
-function getWebProtocol(req: $Request) {
+export function getWebProtocol(req: $Request): string {
   return req.get('X-Forwarded-Proto') || req.protocol;
 }
 
-const getLatestVersion = function(pkgInfo: Package) {
+export function getLatestVersion(pkgInfo: Package): string {
   return pkgInfo[DIST_TAGS].latest;
 };
 
-const ErrorCode = {
-  getConflict: (message: string = 'this package is already present') => {
+export const ErrorCode = {
+  getConflict: (message: string = API_ERROR.PACKAGE_EXIST) => {
     return createError(HTTP_STATUS.CONFLICT, message);
   },
   getBadData: (customMessage?: string) => {
@@ -422,15 +420,16 @@ const ErrorCode = {
   },
 };
 
-const parseConfigFile = (configPath: string) =>
-  YAML.safeLoad(fs.readFileSync(configPath, 'utf8'));
+export function parseConfigFile (configPath: string): Object {
+  return YAML.safeLoad(fs.readFileSync(configPath, CHARACTER_ENCODING.UTF8));
+}
 
 /**
  * Check whether the path already exist.
  * @param {String} path
  * @return {Boolean}
  */
-function folder_exists(path: string) {
+export function folderExists(path: string) {
   try {
     const stat = fs.statSync(path);
     return stat.isDirectory();
@@ -444,7 +443,7 @@ function folder_exists(path: string) {
  * @param {String} path
  * @return {Boolean}
  */
-function fileExists(path: string) {
+export function fileExists(path: string): boolean {
   try {
     const stat = fs.statSync(path);
     return stat.isFile();
@@ -453,7 +452,7 @@ function fileExists(path: string) {
   }
 }
 
-function sortByName(packages: Array<any>): string[] {
+export function sortByName(packages: Array<any>): string[] {
   return packages.sort(function(a, b) {
     if (a.name < b.name) {
       return -1;
@@ -463,11 +462,11 @@ function sortByName(packages: Array<any>): string[] {
   });
 }
 
-function addScope(scope: string, packageName: string) {
+export function addScope(scope: string, packageName: string) {
   return `@${scope}/${packageName}`;
 }
 
-function deleteProperties(propertiesToDelete: Array<string>, objectItem: any) {
+export function deleteProperties(propertiesToDelete: Array<string>, objectItem: any) {
   _.forEach(propertiesToDelete, (property) => {
     delete objectItem[property];
   });
@@ -475,7 +474,7 @@ function deleteProperties(propertiesToDelete: Array<string>, objectItem: any) {
   return objectItem;
 }
 
-function addGravatarSupport(pkgInfo: Object): Object {
+export function addGravatarSupport(pkgInfo: Object): Object {
   const pkgInfoCopy = {...pkgInfo};
   const author = _.get(pkgInfo, 'latest.author', null);
   const contributors = _.get(pkgInfo, 'latest.contributors', []);
@@ -519,7 +518,7 @@ function addGravatarSupport(pkgInfo: Object): Object {
  * @param {String} readme package readme
  * @return {String} converted html template
  */
-function parseReadme(packageName: string, readme: string): string {
+export function parseReadme(packageName: string, readme: string): string {
   if (readme) {
     return marked(readme);
   }
@@ -530,30 +529,6 @@ function parseReadme(packageName: string, readme: string): string {
   return marked('ERROR: No README data found!');
 }
 
-export function buildToken(type: string, token: string) {
+export function buildToken(type: string, token: string): string {
   return `${_.capitalize(type)} ${token}`;
 }
-
-export {
-  addGravatarSupport,
-  deleteProperties,
-  addScope,
-  sortByName,
-  folder_exists,
-  fileExists,
-  parseInterval,
-  semverSort,
-  parse_address,
-  getVersion,
-  tagVersion,
-  combineBaseUrl,
-  validate_metadata,
-  isObject,
-  validateName,
-  validate_package,
-  getWebProtocol,
-  getLatestVersion,
-  ErrorCode,
-  parseConfigFile,
-  parseReadme,
-};
diff --git a/test/unit/api/listen_addr.spec.js b/test/unit/api/listen_addr.spec.js
index 25eabce26..e7ee1ee18 100644
--- a/test/unit/api/listen_addr.spec.js
+++ b/test/unit/api/listen_addr.spec.js
@@ -1,5 +1,5 @@
 import _ from 'lodash';
-import {parse_address as parse} from '../../../src/lib/utils';
+import {parseAddress as parse} from '../../../src/lib/utils';
 import {DEFAULT_DOMAIN, DEFAULT_PORT} from '../../../src/lib/constants';
 
 describe('Parse listen address', () => {