A pem cert with a trust chain can't be read from a variable

[coolov]

My pem cert is a trust chain that begins with a subject, like this:

subject=CN=test-client, O=My Company, L=New York, S=New York, C=US
issuer=CN=My Company T3 001 Certificate Authority G1, DC=nyt, DC=net
-----BEGIN CERTIFICATE-----
MIIHRzCCBi+gAwIBAgITYwAAFnfJ+jbV6pZS7gAHAAAWdzANBgkqhkiG9w0BAQsF
...

Everything works well when I pass the cert via a file path, e.g.:

{
    cert: './client.pem',
    key: './client.key'
 }

But if I pass the cert via a variable it crashes the app:

{
    cert: CLIENT_CERT,  // contains a pem cert with a subject as the first line
    key: CLIENT_KEY
 }

The reason is that the line testing if the variable contains the cert and not a path to the cert evaluates to false. The given cert does not start with -----BEGIN, but with subject=, so this test does not pass:
!/^-----BEGIN/.test(self.options.ssl.cert.toString('utf8'))

Instead of treating the string as a cert, it erroneously treats it as a file path and attempts to use it to load the cert from disk.