Added examples in readme file and support travis ci (#5)

* pass credentials in constructor

* update readme

* added better documentation in read me

* added travis support

* update read me

* update readme

.travis.yml

@@ -0,0 +1,8 @@
+language: node_js
+os:
+  - linux
+  - osx
+node_js:
+  - "node"
+  - 10
+  - 8

README.md

@@ -3,6 +3,8 @@
 This code allows developers to fetch an OAuth token that can be used to call the eBay Developer REST APIs.  The code is intended for use with Node.js.
 
 [![npm version](https://badge.fury.io/js/ebay-oauth-nodejs-client.svg)](https://badge.fury.io/js/ebay-oauth-nodejs-client)
+[![Build Status](https://travis-ci.com/eBay/ebay-oauth-nodejs-client.svg?branch=master)](https://travis-ci.com/github/eBay/ebay-oauth-nodejs-client)
+
 
 ## Table of Contents
 
@@ -33,6 +35,42 @@ or
 
 ```shell
 yarn add ebay-oauth-nodejs-client
+```
+
+## Usage
+
+```js
+const EbayAuthToken = require('ebay-oauth-nodejs-client');
+const ebayAuthToken = new EbayAuthToken({
+    clientId: '<your_client_id>',
+    clientSecret: '<your_client_secret>'.
+    redirectUri: '<redirect uri>'
+});
+// generate client credential token
+(async () => {
+    const token = await ebayAuthToken.getApplicationToken('PRODUCTION');
+    console.log(token);
+})();
+
+// generate user consent authorization url.
+(async () => {
+    const authUrl = await ebayAuthToken.generateUserAuthorizationUrl('PRODUCTION', scopes);
+    console.log(authUrl);
+})();
+
+// Getting a User access token.
+
+(async () => {
+    const accessToken = await ebayAuthToken.exchangeCodeForAccessToken('PRODUCTION', code);
+    console.log(accessToken);
+})();
+
+// Using a refresh token to update a User access token (Updating the expired access token).
+(async () => {
+    const accessToken = await ebayAuthToken.getAccessToken('PRODUCTION', refreshToken, scopes);
+    console.log(accessToken);
+})();
+
 ```
 ## Library Setup and getting started
 

package.json

@@ -1,11 +1,11 @@
 {
   "name": "ebay-oauth-nodejs-client",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Get oauth2 token for ebay developer application",
   "main": "src/index.js",
   "scripts": {
     "lint": "eslint .",
-    "test": "mocha"
+    "test": "eslint . && mocha"
   },
   "author": "Ajaykumar Prathap",
   "license": "ISC",

src/constants.js

@@ -22,7 +22,7 @@ module.exports.OAUTHENVIRONMENT_APIENDPOINT_SANDBOX = 'https://api.sandbox.ebay.
 module.exports.OAUTHENVIRONMENT_APIENDPOINT_PRODUCTION = 'https://api.ebay.com/identity/v1/oauth2/token';
 
 // Scopes
-module.exports.API_SCOPE_SANDBOX = 'https://api.ebay.com/oauth/api_scope';
+module.exports.CLIENT_CRED_SCOPE = 'https://api.ebay.com/oauth/api_scope';
 
 // Environments
 module.exports.PROD_ENV = 'PRODUCTION';

src/index.js

@@ -41,12 +41,19 @@ class EbayOauthToken {
         if (!options) {
             throw new Error('This method accepts an object with filepath or with client id and client secret');
         }
+        // get user credentials.
         this.credentials = options.filePath ? readJSONFile(options.filePath) : readOptions(options);
         this.grantType = '';
         return this;
     }
 
-    getApplicationToken(environment, scopes) {
+    /**
+    * generate application access toke for client credentials grant flow.
+    * @param environment Environment (production/sandbox).
+    * @param scopes array list of scopes for which you need to generate the access token.
+    * @return accessToken object.
+   */
+    getApplicationToken(environment, scopes = consts.CLIENT_CRED_SCOPE) {
         validateParams(environment, scopes, this.credentials);
         this.grantType = consts.PAYLOAD_VALUE_CLIENT_CREDENTIALS;
         this.scope = Array.isArray(scopes) ? scopes.join('%20') : scopes;
@@ -57,6 +64,13 @@ class EbayOauthToken {
         return postRequest(data, this.credentials[environment]);
     }
 
+    /**
+     * generate user consent authorization url.
+     * @param environment Environment (production/sandbox).
+     * @param scopes array list of scopes for which you need to generate the access token.
+     * @param state custom state value.
+     * @return userConsentUrl
+    */
     generateUserAuthorizationUrl(environment, scopes, state) {
         validateParams(environment, scopes, this.credentials);
         const credentials = this.credentials[environment];
@@ -74,6 +88,12 @@ class EbayOauthToken {
         return `${baseUrl}?${queryParam}`;
     }
 
+    /**
+     * Getting a User access token.
+     * @param environment Environment (production/sandbox).
+     * @param code code generated from browser using the method generateUserAuthorizationUrl.
+     * @return accessToken object.
+    */
     exchangeCodeForAccessToken(environment, code) {
         if (!code) {
             throw new Error('Authorization code is required');
@@ -84,6 +104,13 @@ class EbayOauthToken {
         return postRequest(data, credentials);
     }
 
+    /**
+     * Using a refresh token to update a User access token (Updating the expired access token).
+     * @param environment Environment (production/sandbox).
+     * @param refreshToken refresh token.
+     * @param scopes array list of scopes for which you need to generate the access token.
+     * @return accessToken object.
+    */
     getAccessToken(environment, refreshToken, scopes) {
         const token = refreshToken || this.getRefreshToken();
         validateParams(environment, scopes, this.credentials);