Issue #1128 - add snapshot option to FshToFhir

[joepaquette]

Issue #1128 - Enable sushiClient (FshToFhir) to create StructureDefinitions with the snapshot data element

[cmoesel]

Thank you, Joe! I've left one question I'd like your opinion about.

[cmoesel]

Thanks, Joe! This looks great. I did a manual test with the following code and confirmed it is working as expected.

import { sushiClient } from '.';

// Example usage with options
sushiClient
  .fshToFhir(
    `
Profile: MyPatient
Parent: Patient
* name 1..* MS

Profile: MyCondition
Parent: Condition
* subject only Reference(Patient)
`,
    {
      canonical: 'http://example.com',
      version: '1.2.3',
      fhirVersion: '4.0.1',
      snapshot: true
    }
  )
  .then(results => {
    console.log('FHIR', JSON.stringify(results.fhir, null, 2));
    console.log('WARNINGS', JSON.stringify(results.warnings, null, 2));
    console.log('ERRORS', JSON.stringify(results.errors, null, 2));
  })
  .catch(err => {
    console.error('Woah, Nellie!', err);
  });

As you know, we require two code reviews in order to merge, so I'll have someone from the team take a look next week. In the mean time, perhaps you can click the Update Branch button to sync this up with the master branch?

[jafeltra]

Hi @joepaquette! This PR looks good to me as well. I tested it out and looked through the code, and it all looks good to me!

Thanks for addressing this long-standing issue!