nodejs - error self signed certificate in certificate chain

I am facing a problem with client side https requests.

A snippet can look like this:

var fs = require('fs');
var https = require('https');

var options = {
    hostname: 'someHostName.com',
    port: 443,
    path: '/path',
    method: 'GET',
    key: fs.readFileSync('key.key'),
    cert: fs.readFileSync('certificate.crt')
}

var requestGet = https.request(options, function(res){
    console.log('resObj', res);
}

What I get is Error: self signed certificate in certificate chain.

When I use Postman I can import the client certificate and key and use it without any problem. Is there any solution available?? I would also like to be given some lights on how postman handles the certificates and works.

Option 1: Disable the warning (useful for dev)

From your question I'm guessing you are doing this in development as you are using a self signed certificate for SSL communication.

If that's the case, add as an environment variable wherever you are running node

export NODE_TLS_REJECT_UNAUTHORIZED='0'
node app.js

or running node directly with

NODE_TLS_REJECT_UNAUTHORIZED='0' node app.js

This instructs Node to allow untrusted certificates (untrusted = not verified by a certificate authority)

If you don't want to set an environment variable or need to do this for multiple applications npm has a strict-ssl config you set to false

npm config set strict-ssl=false

Option 2: Load in CA cert, like postman (useful for testing with TLS)

If you have a CA cert already like the poster @kDoyle mentioned then you can configure in each request (thanks @nic ferrier).

 let opts = {
    method: 'GET',
    hostname: "localhost",
    port: listener.address().port,
    path: '/',
    ca: fs.readFileSync("cacert.pem")
  };

  https.request(opts, (response) => { }).end();

Option 3: Use a proper SSL Cert from a trusted source (useful for production)

letsencrypt.org is free, easy to set up and the keys can be automatically rotated. https://letsencrypt.org/docs/