feat: add prefix option for metric namespace

.eslintrc.js

@@ -2,4 +2,7 @@
 
 module.exports = {
   extends: "@krakenjs/eslint-config-grumbler/eslintrc-browser",
+  globals: {
+    $Shape: true,
+  },
 };

README.md

@@ -56,6 +56,20 @@ logger.metricCounter({
 })
 ```
 
+#### Using a namespace prefix
+
+```
+const logger = new Logger({...options, metricNamespacePrefix: "company.team.app"})
+
+logger.metricCounter({
+  namespace: "product.feature",
+  event: "button_click",
+})
+
+// creates metric with namespace of
+// company.team.app.product.feature
+```
+
 ### `$logger.metricGauge(<event>, <payload>);`
 
 Queues a gauge metric, helper wrapping `logger.metric`
@@ -71,6 +85,21 @@ logger.metricGauge({
 })
 ```
 
+#### Using a namespace prefix
+
+```
+const logger = new Logger({...options, metricNamespacePrefix: "company.team.app"})
+
+logger.metricGauge({
+  namespace: "product.feature",
+  event: "request_latency",
+  value: 100
+})
+
+// creates metric with namespace of
+// company.team.app.product.feature
+```
+
 ### Deprecated - `$logger.metric(<event>, <payload>);`
 
 Queues a metric. We suggest using the `metricCount` or `metricGauge` interface for better type safety and clearer intention in your code.

src/logger.js

@@ -25,9 +25,10 @@ import type {
   MetricPayloadGauge,
 } from "./types";
 
-type LoggerOptions = {|
+export type LoggerOptions = {|
   url?: string,
   prefix?: string,
+  metricNamespacePrefix?: string,
   logLevel?: $Values<typeof LOG_LEVEL>,
   transport?: Transport,
   flushInterval?: number,
@@ -80,6 +81,7 @@ export type LoggerType = {|
 export function Logger({
   url,
   prefix,
+  metricNamespacePrefix,
   logLevel = DEFAULT_LOG_LEVEL,
   transport = getHTTPTransport(),
   flushInterval = FLUSH_INTERVAL,
@@ -283,6 +285,10 @@ export function Logger({
       return logger; // eslint-disable-line no-use-before-define
     }
 
+    if (metricNamespacePrefix) {
+      metricPayload.metricNamespace = `${metricNamespacePrefix}.${metricPayload.metricNamespace}`;
+    }
+
     if (metricDimensionBuilders.length > 0 && !metricPayload.dimensions) {
       metricPayload.dimensions = {};
     }

src/logger.test.js

@@ -3,7 +3,7 @@
 
 import { beforeEach, describe, expect, test, vi } from "vitest";
 
-import { Logger } from ".";
+import { Logger, type LoggerOptions } from ".";
 
 const XMLHttpRequestMock = vi.fn(() => ({
   open: vi.fn(),
@@ -16,9 +16,13 @@ vi.stubGlobal("XMLHttpRequest", XMLHttpRequestMock);
 let logger;
 let logBuf;
 
-const initLogger = ({ url = "/test/api/log" } = {}) =>
+const initLogger = ({
+  url = "/test/api/log",
+  metricNamespacePrefix,
+}: $Shape<LoggerOptions> = {}) =>
   Logger({
     url,
+    metricNamespacePrefix,
   });
 const getLoggerBuffer = (testLogger) => testLogger.__buffer__;
 
@@ -266,7 +270,7 @@ describe("beaver logger provides flushing methods that send events to the server
 });
 
 describe("metricCounter", () => {
-  test("should add metrics of counter type", () => {
+  test("adds metrics of counter type", () => {
     const testLogger = initLogger();
 
     testLogger.metricCounter({
@@ -306,10 +310,27 @@ describe("metricCounter", () => {
       },
     });
   });
+
+  test("uses metric namespace prefix", () => {
+    const testLogger = initLogger({
+      metricNamespacePrefix: "prefix",
+    });
+
+    testLogger.metricCounter({
+      namespace: "namespace",
+      event: "no_value",
+    });
+
+    expect(getLoggerBuffer(testLogger).metrics[0]).toEqual(
+      expect.objectContaining({
+        metricNamespace: "prefix.namespace",
+      })
+    );
+  });
 });
 
 describe("metricGauge", () => {
-  test("should add metrics of gauge type", () => {
+  test("adds metrics of gauge type", () => {
     const testLogger = initLogger();
 
     testLogger.metricGauge({
@@ -331,10 +352,28 @@ describe("metricGauge", () => {
       },
     });
   });
+
+  test("uses metric namespace prefix", () => {
+    const testLogger = initLogger({
+      metricNamespacePrefix: "prefix",
+    });
+
+    testLogger.metricGauge({
+      namespace: "namespace",
+      event: "load",
+      value: 100,
+    });
+
+    expect(getLoggerBuffer(testLogger).metrics[0]).toEqual(
+      expect.objectContaining({
+        metricNamespace: "prefix.namespace",
+      })
+    );
+  });
 });
 
 describe("addMetricDimensionBuilder", () => {
-  test("should add dimensions from builder", () => {
+  test("adds dimensions from builder", () => {
     const testLogger = initLogger();
 
     testLogger.addMetricDimensionBuilder(() => ({
@@ -356,7 +395,7 @@ describe("addMetricDimensionBuilder", () => {
     );
   });
 
-  test("should overwrite existing dimensions", () => {
+  test("overwrites existing dimensions", () => {
     const testLogger = initLogger();
 
     testLogger.addMetricDimensionBuilder(() => ({
@@ -385,7 +424,7 @@ describe("addMetricDimensionBuilder", () => {
     );
   });
 
-  test("should merge dimensions", () => {
+  test("merges dimensions", () => {
     const testLogger = initLogger();
 
     testLogger.addMetricDimensionBuilder(() => ({