Let's say you want to use 'npm install mssql --save' but can't get connected to your local server.
You probably need to check these things:
- Ensure you can connect manually through SQL Server management studio
- Provide connection info to clients by turning on mssql browser service
- Services > SQL Server Browser
- Check Sql Server Network Configuration
- Start > SQL Server Configuration Manager > SQL Server Network Configurations > enable TCP/IP
- On property tab of protocol ensure IP ALL has no dynamics and 1433 as port with 127.0.0.1 enabled
- Restart server instance