How to connect couchDB to angular4 app using Node.js and express

I am new to angular4/angular CLI. Actually, i develope the angular4 project and my database is CouchDB and project are running still but values are saved in browser table, and these are not saved in couchDB.I am Also given database connection add router code.Where to get the error are not identified me .How do I create database connection to angular4/Cli project any another way to please send me the Example code, I refer the code is [].Please give me connection code.