Conditionally import cross-fetch with polyfill - Issue #197

README.md

@@ -185,6 +185,10 @@ DEBUG environment variable, or use `fhir-kit-client:*` to enable both.
 $ DEBUG=fhir-kit-client:* node smart-launch.js
 ```
 
+## Disabling Fetch Polyfill
+
+The optional polyfill in the cross-fetch package can be disabled by setting the environmnt variable FETCH_POLYFILL=disable.
+
 ## Contributing
 
 FHIRKit Client is an open source Node.js FHIR client library that welcomes

lib/http-client.js

@@ -1,6 +1,12 @@
+/* eslint-disable global-require */
 /* global Request, Headers */
 require('es6-promise').polyfill();
-require('cross-fetch/polyfill');
+
+if (process.env.FETCH_POLYFILL && process.env.FETCH_POLYFILL === 'disable') {
+  require('cross-fetch');
+} else {
+  require('cross-fetch/polyfill');
+}
 
 const { logRequestError, logRequestInfo, logResponseInfo } = require('./logging');