I am getting npm error UNABLE_TO_GET_ISSUER_CERT_LOCALLY upon trying to install npm package most likely because i am behind corporate proxy. I saw this which gives a possible solution to add NODE_EXTRA_CA_CERTS as path variable and point it to pem file. I searched for .pem file in C drive and found few inside C:\Windows\System32\DriverStore\FileRepository\ folder, but npm gives the same error if i use them. Also referred this for generating pem using openssl but it's not working for me. 
Question: Where to locate .pem file in Windows or how to generate one for above use case.
 
    