Watches a local npm package directory and serves FHIR resources with FHIRPath-based search indexes. Part of the FHIR Development Server.

• Hot reload: Automatically rebuilds indexes when files in the watched directory change
• Atomic swap: In-flight requests complete against consistent data during reloads
• FHIRPath-based indexing: Uses fhirpath library to evaluate SearchParameter expressions
• Standard FHIR search: Supports string, token, reference, date, quantity, number, and uri parameter types
• Bundle support: Automatically extracts resources from FHIR Bundles

Add to your config.json:

{
  "modules": {
    "npmprojector": {
      "enabled": true,
      "basePath": "/fhir",
      "npmPath": "/path/to/fhir/package.tgz",
      "fhirVersion": "r4",
      "resourceTypes": ["Medication"],
      "resourceFolders": ["data/medications"],
      "searchParametersFolder": "data/search",
      "searchParametersPath": "/path/to/external/search-params",
      "debounceMs": 500
    }
  }
}

resourceFolders: Only load resources from specific subfolders within the package. Paths are relative to the package root. If not specified, all folders are scanned.

"resourceFolders": ["data/medications", "data/patients"]

searchParametersFolder: Load SearchParameters from a specific subfolder within the package (instead of finding them mixed in with resources).

"searchParametersFolder": "data/search"

searchParametersPath: Load SearchParameters from an external location (outside the package). This is useful for loading standard FHIR search parameters.

"searchParametersPath": "/Users/you/.fhir/packages/hl7.fhir.r4.core#4.0.1/package"

Both searchParametersFolder and searchParametersPath can be used together - they will be merged.

Add to server.js:

const NpmProjectorModule = require('./npmprojector/npmprojector.js');

// In initializeModules():
if (config.modules.npmprojector && config.modules.npmprojector.enabled) {
  try {
    modules.npmprojector = new NpmProjectorModule();
    await modules.npmprojector.initialize(config.modules.npmprojector);
    
    // Use configured basePath or default
    const basePath = NpmProjectorModule.getBasePath(config.modules.npmprojector);
    app.use(basePath, modules.npmprojector.router);
  } catch (error) {
    serverLog.error('Failed to initialize NpmProjector module:', error);
    throw error;
  }
}

# Get all patients
curl http://localhost:3000/npmprojector/Patient

# Search by family name (case-insensitive, starts-with)
curl "http://localhost:3000/npmprojector/Patient?family=smith"

# Search by gender (token)
curl "http://localhost:3000/npmprojector/Patient?gender=male"

# Search by identifier with system
curl "http://localhost:3000/npmprojector/Patient?identifier=http://example.org/mrn|12345"

# Search observations by code (LOINC)
curl "http://localhost:3000/npmprojector/Observation?code=http://loinc.org|8867-4"

# OR search (comma-separated)
curl "http://localhost:3000/npmprojector/Patient?gender=male,female"

# Multiple parameters (AND)
curl "http://localhost:3000/npmprojector/Patient?family=smith&gender=male"

The watched directory should contain JSON files with FHIR resources:

your-fhir-package/
├── resources.json          # Bundle of Patient, Observation, etc.
├── search-parameters.json  # Bundle of SearchParameter definitions
└── more-data/
    └── additional.json     # More resources (recursively loaded)

SearchParameter resources can be:

1. Mixed in with other resources in the watched directory
2. Loaded from a separate searchParametersPath location
3. Both (they will be merged)

• Read-only: No create/update/delete operations
• No chained search: subject.name=John not supported
• No _include/_revinclude: Related resources not included
• No date ranges: ge, le, gt, lt prefixes not supported
• No composite parameters: Multi-field search params not supported
• No modifiers: :exact, :contains, :missing not supported

Requires fhirpath, chokidar, and tar packages:

npm install fhirpath chokidar tar