feat(node-sdk): Improve feature overrides (#437)

- include a testing section
- rewrote many tests for Client because it was difficult to work with
because of mocking and many asserts.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: roncohen

packages/node-sdk/README.md

@@ -403,6 +403,43 @@ bucketClient.initialize().then(() => {
 
 ![Config type check failed](docs/type-check-payload-failed.png "Remote config type check failed")
 
+## Testing
+
+When writing tests that cover code with feature flags, you can toggle features on/off programmatically to test the different behavior.
+
+`bucket.ts`:
+
+```typescript
+import { BucketClient } from "@bucketco/node-sdk";
+
+export const bucket = new BucketClient();
+```
+
+`app.test.ts`:
+
+```typescript
+import { bucket } from "./bucket.ts";
+
+beforeAll(async () => await bucket.initialize());
+afterEach(() => {
+  bucket.clearFeatureOverrides();
+});
+
+describe("API Tests", () => {
+  it("should return 200 for the root endpoint", async () => {
+    bucket.featureOverrides = {
+      "show-todo": true,
+    };
+
+    const response = await request(app).get("/");
+    expect(response.status).toBe(200);
+    expect(response.body).toEqual({ message: "Ready to manage some TODOs!" });
+  });
+});
+```
+
+See more on feature overrides in the section below.
+
 ## Feature Overrides
 
 Feature overrides allow you to override feature flags and their configurations locally. This is particularly useful for development and testing. You can specify overrides in three ways:
@@ -414,7 +451,7 @@ BUCKET_FEATURES_ENABLED=feature1,feature2
 BUCKET_FEATURES_DISABLED=feature3,feature4
 ```
 
-1. Through `bucketConfig.json`:
+2. Through `bucketConfig.json`:
 
 ```json
 {
@@ -433,7 +470,21 @@ BUCKET_FEATURES_DISABLED=feature3,feature4
 }
 ```
 
-1. Programmatically through the client options:
+3. Programmatically through the client options:
+
+You can use a simple `Record<string, boolean>` and pass it either in the constructor or by setting `client.featureOverrides`:
+
+```typescript
+// pass directly in the constructor
+const client = new BucketClient({ featureOverrides: { myFeature: true } });
+// or set on the client at a later time
+client.featureOverrides = { myFeature: false };
+
+// clear feature overrides. Same as setting to {}.
+client.clearFeatureOverrides();
+```
+
+To get dynamic overrides, use a function which takes a context and returns a boolean or an object with the shape of `{isEnabled, config}`:
 
 ```typescript
 import { BucketClient, Context } from "@bucketco/node-sdk";

packages/node-sdk/example/app.test.ts

@@ -6,9 +6,9 @@ import bucket from "./bucket";
 
 beforeAll(async () => await bucket.initialize());
 beforeEach(() => {
-  bucket.featureOverrides = () => ({
+  bucket.featureOverrides = {
     "show-todos": true,
-  });
+  };
 });
 
 describe("API Tests", () => {

packages/node-sdk/src/client.ts

@@ -21,6 +21,7 @@ import type {
   EvaluatedFeaturesAPIResponse,
   FeatureAPIResponse,
   FeatureDefinition,
+  FeatureOverrides,
   FeatureOverridesFn,
   IdType,
   RawFeature,
@@ -338,9 +339,38 @@ export class BucketClient {
    * @remarks
    * The feature overrides are used to override the feature definitions.
    * This is useful for testing or development.
+   *
+   * @example
+   * ```ts
+   * client.featureOverrides = {
+   *   "feature-1": true,
+   *   "feature-2": false,
+   * };
+   * ```
+   **/
+  set featureOverrides(overrides: FeatureOverridesFn | FeatureOverrides) {
+    if (typeof overrides === "object") {
+      this._config.featureOverrides = () => overrides;
+    } else {
+      this._config.featureOverrides = overrides;
+    }
+  }
+
+  /**
+   * Clears the feature overrides.
+   *
+   * @remarks
+   * This is useful for testing or development.
+   *
+   * @example
+   * ```ts
+   * afterAll(() => {
+   *   client.clearFeatureOverrides();
+   * });
+   * ```
    **/
-  set featureOverrides(overrides: FeatureOverridesFn) {
-    this._config.featureOverrides = overrides;
+  clearFeatureOverrides() {
+    this._config.featureOverrides = () => ({});
   }
 
   /**
@@ -1107,11 +1137,17 @@ export class BucketClient {
       this._config.featureOverrides(context),
     ).map(([key, override]) => [
       key,
-      {
-        key,
-        isEnabled: isObject(override) ? override.isEnabled : !!override,
-        config: isObject(override) ? override.config : undefined,
-      },
+      isObject(override)
+        ? {
+            key,
+            isEnabled: override.isEnabled,
+            config: override.config,
+          }
+        : {
+            key,
+            isEnabled: !!override,
+            config: undefined,
+          },
     ]);
 
     if (overrides.length > 0) {