fix: correctly get and set top level contentType property (#625)

Author: SimenB

CHANGELOG.md

@@ -12,6 +12,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Add `Registry.PROMETHEUS_CONTENT_TYPE` and `Registry.OPENMETRICS_CONTENT_TYPE` constants to the TypeScript types
+- Correctly read and set `contentType` top level export
 
 ### Added
 

index.d.ts

@@ -81,7 +81,7 @@ export class Registry<RegistryContentType = PrometheusContentType> {
 	/**
 	 * Gets the Content-Type of the metrics for use in the response headers.
 	 */
-	contentType: RegistryContentType;
+	readonly contentType: RegistryContentType;
 
 	/**
 	 * Set the content type of a registry. Used to change between Prometheus and
@@ -114,8 +114,8 @@ export type Collector = () => void;
 export const register: Registry;
 
 /**
- * HTTP Content-Type for metrics response headers, defaults to Prometheus text
- * format.
+ * HTTP Content-Type for metrics response headers for the default registry,
+ * defaults to Prometheus text format.
  */
 export const contentType: RegistryContentType;
 

index.js

@@ -7,11 +7,18 @@
 
 exports.register = require('./lib/registry').globalRegistry;
 exports.Registry = require('./lib/registry');
-exports.contentType = require('./lib/registry').globalRegistry.contentType;
-exports.prometheusContentType =
-	require('./lib/registry').PROMETHEUS_CONTENT_TYPE;
-exports.openMetricsContentType =
-	require('./lib/registry').OPENMETRICS_CONTENT_TYPE;
+Object.defineProperty(exports, 'contentType', {
+	configurable: false,
+	enumerable: true,
+	get() {
+		return exports.register.contentType;
+	},
+	set(value) {
+		exports.register.setContentType(value);
+	},
+});
+exports.prometheusContentType = exports.Registry.PROMETHEUS_CONTENT_TYPE;
+exports.openMetricsContentType = exports.Registry.OPENMETRICS_CONTENT_TYPE;
 exports.validateMetricName = require('./lib/validation').validateMetricName;
 
 exports.Counter = require('./lib/counter');