Complete source code to showcase using Lightning component in node.js (External websites) by using Lightning Out. It shows how to enable CORS and SSL in Node.js with Video and complete source code.
Steps to run
Create below Lightning application in your Salesforce instance and name it as LightningOutDemo
<aura:application access="Global" extends="ltng:outApp">
<aura:dependency resource="forceChatter:feed" type="COMPONENT" />
Create Connected App in your Salesforce instance with callback URL -
Copy consumer secret created in connected app and update clientId variable defined in OAuth.js file.
https://localhost:8081 in CORS setting of Salesforce.
npm install command in the directory where this code is downloaded. It will download all the required node modules.
npm start, it will start the server
https://localhost:8081/ in your browser and you would see Lightning Out in Action