add feature filter doc

Author: zhiyuanliang-ms

articles/azure-app-configuration/TOC.yml

@@ -138,6 +138,8 @@
         href: howto-feature-filters.md
       - name: ASP.NET Core
         href: howto-feature-filters-aspnet-core.md
+      - name: Node.js
+        href: howto-feature-filters-javascript.md
       - name: Python
         href: howto-feature-filters-python.md
     - name: Enable features on a schedule
@@ -146,6 +148,8 @@
         href: howto-timewindow-filter.md
       - name: ASP.NET Core
         href: howto-timewindow-filter-aspnet-core.md
+      - name: Node.js
+        href: howto-timewindow-filter-javascript.md
     - name: Roll out features to targeted audience
       items:
       - name: Overview

articles/azure-app-configuration/howto-feature-filters-javascript.md

@@ -0,0 +1,82 @@
+---
+title: Enable conditional features with a custom filter in a Node.js application
+titleSuffix: Azure App Configuration
+description: Learn how to implement a custom feature filter to enable conditional feature flags for your Node.js application.
+ms.service: azure-app-configuration
+ms.devlang: javascript
+ms.custom: devx-track-csharp
+author: zhiyuanliang-ms
+ms.author: zhiyuanliang
+ms.topic: how-to
+ms.custom: mode-other, devx-track-js
+ms.date: 09/26/2024
+---
+
+# Tutorial: Enable conditional features with a custom filter in a Node.js application
+
+Feature flags can use feature filters to enable features conditionally. To learn more about feature filters, see [Tutorial: Enable conditional features with feature filters](./howto-feature-filters.md).
+
+The example used in this tutorial is based on the Node.js application introduced in the feature management [quickstart](./quickstart-feature-flag-javascript.md). Before proceeding further, complete the quickstart to create a Node.js application with a *Beta* feature flag. Once completed, you must [add a custom feature filter](./howto-feature-filters.md) to the *Beta* feature flag in your App Configuration store. 
+
+In this tutorial, you'll learn how to implement a custom feature filter and use the feature filter to enable features conditionally.
+
+## Prerequisites
+
+- Create a [Node.js app with a feature flag](./quickstart-feature-flag-javascript.md).
+- [Add a custom feature filter to the feature flag](./howto-feature-filters.md)
+
+## Implement a custom feature filter
+
+You've added a custom feature filter named **Random** with a **Percentage** parameter for your *Beta* feature flag in the prerequisites. Next, you implement the feature filter to enable the *Beta* feature flag based on the chance defined by the **Percentage** parameter.
+
+1. Open the file *app.js* and add the `RandomFilter` with the following code.
+
+    ``` javascript
+    class RandomFilter {
+        name = "Random";
+        evaluate(context) {
+            const percentage = context.parameters.Percentage;
+            const randomNumber = Math.random() * 100;
+            return randomNumber <= percentage;
+        }
+    }
+    ```
+
+    You added a `RandomFilter` class that has a single method named `evaluate`, which is called whenever a feature flag is evaluated. In `evaluate`, a feature filter enables a feature flag by returning `true`.
+
+    You set the name to of `RandomFilter` to **Random**, which matches the filter name you set in the *Beta* feature flag in Azure App Configuration.
+
+1. Register the `RandomFilter` when creating the `FeatureManager`.
+
+    ``` javascript
+    const fm = new FeatureManager(ffProvider, {customFilters: [new RandomFilter()]});
+    ```
+
+## Feature filter in action
+
+When you run the application the configuration provider will load the *Beta* feature flag from Azure App Configuration. The result of the `isEnabled("Beta")` method will be printed to the console. As the `RandomFilter` is implemented and used by the *Beta* feature flag, the result will be `True` 50 percent of the time and `False` the other 50 percent of the time.
+
+Running the application will show that the *Beta* feature flag is sometimes enabled and sometimes not.
+
+``` bash
+Beta is enabled: true
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: true
+Beta is enabled: true
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: true
+Beta is enabled: true
+```
+
+## Next steps
+
+To learn more about the built-in feature filters, continue to the following tutorials.
+
+> [!div class="nextstepaction"]
+> [Enable features on a schedule](./howto-timewindow-filter.md)
+
+> [!div class="nextstepaction"]
+> [Roll out features to targeted audience](./howto-targetingfilter.md)

articles/azure-app-configuration/howto-feature-filters.md

@@ -66,6 +66,9 @@ To learn how to implement a custom feature filter, continue to the following tut
 > [!div class="nextstepaction"]
 > [ASP.NET Core](./howto-feature-filters-aspnet-core.md)
 
+> [!div class="nextstepaction"]
+> [Node.js](./howto-feature-filters-javascript.md)
+
 > [!div class="nextstepaction"]
 > [Python](./howto-feature-filters-python.md)
 

articles/azure-app-configuration/howto-timewindow-filter-javascript.md

@@ -0,0 +1,65 @@
+---
+title: Enable features on a schedule in a Node.js application
+titleSuffix: Azure App Configuration
+description: Learn how to enable feature flags on a schedule in a Node.js application.
+ms.service: azure-app-configuration
+ms.devlang: javascript
+author: zhiyuanliang-ms
+ms.author: zhiyuanliang
+ms.topic: how-to
+ms.custom: mode-other, devx-track-js
+ms.date: 09/26/2024
+---
+
+# Tutorial: Enable features on a schedule in an ASP.NET Core application
+
+In this tutorial, you use the time window filter to enable a feature on a schedule for a Node.js application. 
+
+The example used in this tutorial is based on the Node.js application introduced in the feature management [quickstart](./quickstart-feature-flag-javascript.md). Before proceeding further, complete the quickstart to create an ASP.NET Core application with a *Beta* feature flag. Once completed, you must [add a time window filter](./howto-timewindow-filter.md) to the *Beta* feature flag in your App Configuration store.
+
+## Prerequisites
+
+- Create a [Node.js application with a feature flag](./quickstart-feature-flag-javascript.md).
+- [Add a time window filter to the feature flag](./howto-timewindow-filter.md)
+
+## Use the time window filter
+
+You've added a time window filter for your *Beta* feature flag in the prerequisites. Next, you'll use the feature flag with the time window filter in your Node.js application.
+
+When you create a feature manager, the built-in feature filters will be automatically added to its feature filter collection.
+
+``` javascript
+// The Microsoft.TimeWindow and Microsoft.Targeting filters are auto-included, so you can use them directly in your feature flags.
+const fm = new FeatureManager(ffProvider);
+```
+
+## Time window filter in action
+
+When you run the application the configuration provider will load the *Beta* feature flag from Azure App Configuration. The result of the `isEnabled("Beta")` method will be printed to the console. If your current time is earlier than the start time set for the time window filter, the *Beta* feature flag will be disabled by the time window filter.
+
+Once the start time has passed, you'll notice that the *Beta* feature flag is enabled by the time window filter.
+
+You will see the following console outputs.
+
+``` bash
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: false
+Beta is enabled: true
+Beta is enabled: true
+Beta is enabled: true
+Beta is enabled: true
+```
+
+## Next steps
+
+To learn more about the feature filters, continue to the following tutorials.
+
+> [!div class="nextstepaction"]
+> [Enable conditional features with feature filters](./howto-feature-filters.md)
+
+> [!div class="nextstepaction"]
+> [Roll out features to targeted audience](./howto-targetingfilter.md)

articles/azure-app-configuration/howto-timewindow-filter.md

@@ -50,6 +50,9 @@ To learn how to use the feature flag with a time window filter in your applicati
 > [!div class="nextstepaction"]
 > [ASP.NET Core](./howto-timewindow-filter-aspnet-core.md)
 
+> [!div class="nextstepaction"]
+> [Node.js](./howto-timewindow-filter-javascript.md)
+
 To learn more about the feature filters, continue to the following tutorials:
 
 > [!div class="nextstepaction"]

articles/azure-app-configuration/index.yml

@@ -148,6 +148,8 @@ landingContent:
           url: quickstart-feature-flag-spring-boot.md
         - text: Python app
           url: quickstart-feature-flag-python.md
+        - text: Node.js app
+          url: quickstart-feature-flag-javascript.md
       - linkListType: tutorial
         links: 
         - text: Use feature flags in ASP.NET Core