feat(flags): document statsig browser integration

docs/platforms/javascript/common/configuration/integrations/statsig.mdx

@@ -0,0 +1,40 @@
+---
+title: Statsig
+description: "Learn how to use Sentry with Statsig."
+notSupported:
+  - javascript.aws-lambda
+  - javascript.azure-functions
+  - javascript.bun
+  - javascript.capacitor
+  - javascript.cloudflare
+  - javascript.connect
+  - javascript.cordova
+  - javascript.deno
+  - javascript.electron
+  - javascript.express
+  - javascript.fastify
+  - javascript.gcp-functions
+  - javascript.hapi
+  - javascript.koa
+  - javascript.nestjs
+  - javascript.nodejs
+  - javascript.wasm
+---
+
+<PlatformContent includePath="feature-flags/prerelease-alert" />
+
+<Alert level="info">
+
+This integration only works inside a browser environment. It is only available from a package-based install (e.g. `npm` or `yarn`).
+
+</Alert>
+
+The [Statsig](https://www.statsig.com/) integration tracks feature flag evaluations produced by the Statsig SDK. These evaluations are held in memory, and in the event an error occurs, sent to Sentry for review and analysis. **At the moment, we only support boolean flag evaluations from Statsig's `checkGate` method**. Learn more about [feature gates](https://docs.statsig.com/feature-flags/working-with/).
+
+This integration is available in Sentry SDK **versions 9.0.0 and higher**, or **versions 8.55.0 and higher for v8.**
+
+_Import name: `Sentry.statsigIntegration`_
+
+<PlatformContent includePath="/configuration/statsig" />
+
+<PlatformContent includePath="feature-flags/next-steps" />

docs/platforms/javascript/common/feature-flags/index.mdx

@@ -35,6 +35,7 @@ Evaluation tracking requires enabling an SDK integration. Integrations are provi
 - [Generic](/platforms/javascript/configuration/integrations/featureflags/)
 - [LaunchDarkly](/platforms/javascript/configuration/integrations/launchdarkly/)
 - [OpenFeature](/platforms/javascript/configuration/integrations/openfeature/)
+- [Statsig](/platforms/javascript/configuration/integrations/statsig/)
 - [Unleash](/platforms/javascript/configuration/integrations/unleash/)
 
 ## Enable Change Tracking

platform-includes/configuration/integrations/javascript.mdx

@@ -25,4 +25,5 @@
 | [`replayIntegration`](./replay)                       |                  |            |             |     ✓      |           ✓            |
 | [`replayCanvasIntegration`](./replaycanvas)           |                  |            |             |     ✓      |                        |
 | [`reportingObserverIntegration`](./reportingobserver) |                  |     ✓      |             |            |                        |
+| [`statsigIntegration`](./statsig)                     |                  |            |             |            |           ✓            |
 | [`unleashIntegration`](./unleash)                     |                  |            |             |            |           ✓            |

platform-includes/configuration/statsig/javascript.mdx

@@ -0,0 +1,20 @@
+Before using this integration, you need to install and instrument Statsig in your app. Learn more by reading [Statsig's SDK reference](https://docs.statsig.com/client/javascript-sdk) and [quickstart guide](https://docs.statsig.com/guides/first-feature).
+
+```javascript
+import * as Sentry from '@sentry/browser';
+import { StatsigClient } from '@statsig/js-client';
+
+const statsigClient = new StatsigClient( YOUR_SDK_KEY, { userID: 'my-user-id' }, {} ); // see SDK reference.
+
+Sentry.init({
+  dsn: '___PUBLIC_DSN___',
+  integrations: [Sentry.statsigIntegration({featureFlagClient: statsigClient})],
+});
+
+await statsigClient.initializeAsync();  // or statsigClient.initializeSync();
+
+const result = statsigClient.checkGate('my-feature-gate');
+Sentry.captureException(new Error('something went wrong'));
+```
+
+Visit the Sentry website and confirm that your error event has recorded the feature flag "my-feature-gate" and its value "false".