Power BI Secure Embed (User Owns Data) & Single Sign-on integration using JavaScript

Hello - 

We're using Power BI Premium Capacity and trying to embed Power BI Reports to ServiceNow Portal (JavaScript) and here is the scenario. 

1. It is Secure Embed.
2. It is for our Organization, so user owns data. 
3. ServiceNow Portal uses the same Azure Active Directory as Power BI does.
4. In this custom integration, we want to implement Single Sign-on so that users don't have to sign in again to view the reports while being on the ServiceNow Portal. 
5. All custom code has to be JavaScript, because it will go with ServiceNow Portal Page. 

Is this possible using JavaScript? Here is what we've tried so far. 

1. Created Azure AD Web App and got the ClientID and Client Secret.
2. Get Azure AD Authorization Code using Web App - We're able to execute below URL and get the Authorization code in the URL. We couldn't find JavaScript code to generate this Authorization code using GET method.

   https://login.windows.net/common/oauth2/authorize?client_id=<<clientid>>&response_type=code&redirect_uri=<<redirecturi>>

3. Successfully generated Bearer Access Token using Post API - https://login.microsoftonline.com/common/oauth2/token
4. Once got the access token, we're able to embed the report using JavaScript. 

Can we please get any help on #2? 

Thank you.