feat: add client context mutation (open-feature#207)

Adding this for consistency with other SDKs.

Signed-off-by: Todd Baert <[email protected]>

src/client.ts

@@ -21,7 +21,7 @@ type OpenFeatureClientOptions = {
 
 export class OpenFeatureClient implements Client {
   readonly metadata: ClientMetadata;
-  readonly context: EvaluationContext;
+  private _context: EvaluationContext;
   private _hooks: Hook[] = [];
 
   constructor(
@@ -35,7 +35,15 @@ export class OpenFeatureClient implements Client {
       name: options.name,
       version: options.version,
     } as const;
-    this.context = context;
+    this._context = context;
+  }
+
+  set context (context: EvaluationContext) {
+    this._context = context;
+  }
+
+  get context (): EvaluationContext {
+    return this._context;
   }
 
   addHooks(...hooks: Hook<FlagValue>[]): void {
@@ -159,7 +167,7 @@ export class OpenFeatureClient implements Client {
     // merge global and client contexts
     const mergedContext = {
       ...OpenFeature.context,
-      ...this.context,
+      ...this._context,
       ...invocationContext,
     };
 

src/types.ts

@@ -211,6 +211,7 @@ export type EvaluationDetails<T extends FlagValue> = {
 
 export interface Client extends EvaluationLifeCycle, Features {
   readonly metadata: ClientMetadata;
+  context: EvaluationContext;
 }
 
 export type HookHints = Readonly<Record<string, unknown>>;

test/client.spec.ts

@@ -407,5 +407,15 @@ describe(OpenFeatureClient.name, () => {
         );
       });
     });
+
+    describe('client evaluation context', () => {
+      it('can be mutated', async () => {
+        const KEY = 'key';
+        const VAL = 'val';
+        const client = OpenFeature.getClient();
+        client.context = { [KEY]: VAL };
+        expect(client.context[KEY]).toEqual(VAL);
+      });
+    });
   });
 });