diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..e85cf81
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,5 @@
+[*]
+indent_size = 2
+indent_style = space
+max_line_length = 120
+tab_width = 2
\ No newline at end of file
diff --git a/.eslintrc.js b/.eslintrc.js
new file mode 100644
index 0000000..64c3b03
--- /dev/null
+++ b/.eslintrc.js
@@ -0,0 +1,24 @@
+module.exports = {
+  extends: ['eslint:recommended', 'prettier'], // extending recommended config and config derived from eslint-config-prettier
+  plugins: ['prettier'], // extending recommended config and config derived from eslint-config-prettier
+  env: {
+    browser: true,
+    node: true,
+    amd: true,
+    es6: true,
+    commonjs: true,
+    jest: true,
+  },
+  parser: 'babel-eslint',
+  rules: {
+    'prettier/prettier': [
+      // customizing prettier rules (unfortunately not many of them are customizable)
+      'error',
+      {
+        singleQuote: true,
+        tabWidth: 2,
+      },
+    ],
+    eqeqeq: ['error', 'always'], // adding some custom ESLint rules
+  },
+};
diff --git a/README.md b/README.md
index fe23119..55089cd 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ $ npm install add-dependencies [-g]
 
 ### Usage
 
-Run:
+Run (for `nodejs` see Example):
 
 ```sh
 $ add-dependencies [package_file] <dependencies> [target] [--no-overwrite]
@@ -46,3 +46,20 @@ or with `npx`:
 ```sh
 $ npx add-dependencies /home/user/project/package.json moment@2.0.0 react@16.8 redux eslint --dev
 ```
+
+or via nodejs
+
+```js
+const npmAdd = require('add-dependencies/lib/AddDependencies');
+const dependencies = [
+    'package1',
+    'package2',
+    'package3',
+];
+const target = npmAdd.CONSTANTS.DEPENDENCIES;
+const overwrite = false;
+const packageFilePath = 'package.json';
+new npmAdd(dependencies, target, overwrite, packageFilePath)
+    .run()
+    .then(() => console.log('completed'));
+```
\ No newline at end of file
diff --git a/cli-index.js b/cli-index.js
new file mode 100755
index 0000000..7f37807
--- /dev/null
+++ b/cli-index.js
@@ -0,0 +1,17 @@
+#!/usr/bin/env node
+const AddDependencies = require('./lib/AddDependencies');
+
+console.log(
+  '\x1b[33m%s\x1b[0m',
+  'This script adds dependencies (latest or specified versions) to the package.json file skipping the installation process.'
+);
+
+const app = new AddDependencies();
+
+app
+  .addDependencies()
+  .then(app.saveToPackage.bind(app))
+  .catch((error) => {
+    console.error('\x1b[31m%s\x1b[0m', error);
+    process.exit(1);
+  });
diff --git a/index.js b/index.js
index 1e8cf44..23c368d 100755
--- a/index.js
+++ b/index.js
@@ -1,11 +1,2 @@
 #!/usr/bin/env node
-const AddDependencies = require('./lib/AddDependencies');
-
-console.log('\x1b[33m%s\x1b[0m', 'This script adds dependencies (latest or specified versions) to the package.json file skipping the installation process.');
-
-const app = new AddDependencies();
-
-app.addDependencies().then(app.saveToPackage.bind(app)).catch((error) => {
-  console.error('\x1b[31m%s\x1b[0m', error);
-  process.exit(1);
-});
+module.exports = require('./lib/AddDependencies');
diff --git a/lib/AddDependencies.js b/lib/AddDependencies.js
index 8b78554..e377036 100644
--- a/lib/AddDependencies.js
+++ b/lib/AddDependencies.js
@@ -3,12 +3,16 @@ const semver = require('semver');
 const Files = require('./Files');
 
 class AddDependencies {
-  constructor() {
+  constructor(dependencies = [],
+              target = 'dependencies',
+              overwrite = true,
+              packageFilePath =  './package.json'
+  ) {
     this.result = {};
-    this.dependencies = [];
-    this.target = 'dependencies';
-    this.overwrite = true;
-    this.packageFilePath = './package.json';
+    this.dependencies = dependencies;
+    this.target = target;
+    this.overwrite = overwrite;
+    this.packageFilePath = packageFilePath;
   }
 
   addDependencies() {
@@ -56,7 +60,15 @@ class AddDependencies {
 
     console.log(`Adding packages to '${this.target}'...`);
 
-    return Promise.all(this.dependencies.map((dep) => this.runNpmShow(dep)));
+    return this.mapDependencies();
+  }
+
+  mapDependencies() {
+    return Promise.all(this.dependencies.map((dep) => this.runNpmShow(dep)))
+  }
+
+  run(){
+    return this.mapDependencies().then(() => this.saveToPackage())
   }
 
   runNpmShow(dep) {
@@ -158,6 +170,15 @@ class AddDependencies {
       process.exit(1);
     });
   }
+
+  static get CONSTANTS() {
+    return {
+      DEPENDENCIES: 'dependencies',
+      DEV_DEPENDENCIES: 'devDependencies',
+      PEER_DEPENDENCIES: 'peerDependencies',
+      OPTIONAL_DEPENDENCIES: 'optionalDependencies',
+    };
+  }
 }
 
 module.exports = AddDependencies;
diff --git a/package.json b/package.json
index 6fa9dc1..5de0b67 100644
--- a/package.json
+++ b/package.json
@@ -12,6 +12,7 @@
   "homepage": "https://github.com/arfeo/npm-add-dependencies#readme",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
+    "lint": "eslint --fix --ext js lib/**.js index.js"
   },
   "keywords": [
     "dependencies",
@@ -23,10 +24,17 @@
   "license": "MIT",
   "preferGlobal": true,
   "bin": {
-    "add-dependencies": "index.js"
+    "add-dependencies": "cli-index.js"
   },
   "dependencies": {
     "npm-run": "^5.0.1",
     "semver": "^6.3.0"
+  },
+  "devDependencies": {
+    "eslint": "^7.3.0",
+    "babel-eslint": "^10.1.0",
+    "eslint-config-prettier": "^3.3.0",
+    "eslint-plugin-prettier": "^3.0.0",
+    "prettier": "^2.0.5"
   }
 }