axios custom httpAgent with root certificate

index.js

const https = require('https');
const axios = require('axios');
const fs = require('fs');

const httpsAgent = new https.Agent({
    requestCert: true,
    rejectUnauthorized: true,
    ca: [fs.readFileSync('./root_cert.pem')],
    // cert: [fs.readFileSync('./cert.pem')]
});

const getData = async () => {
    try {
        const data = await axios({
            url: 'https://api-cool.com/v1/people',
            method: 'get',
            auth: {
                username: 'user',
                password: '695849d'
            },
            httpsAgent: httpsAgent
        });
    
        console.log(data);
    } catch(e) {
        console.log('error...');
        console.log(e);
    }
}

getData();

root_cert.pem

-----BEGIN CERTIFICATE-----
long certificate
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
short root cert
-----END CERTIFICATE-----