refactor: update go feature flag provider to use not deprecated context transformer (open-feature#92)

Signed-off-by: Michael Beemer <[email protected]>

Author: beeme1mr

libs/providers/go-feature-flag/src/lib/context-transfomer.spec.ts

@@ -0,0 +1,70 @@
+import { EvaluationContext } from '@openfeature/nodejs-sdk';
+import { GoFeatureFlagUser } from './model';
+import { transformContext } from './context-transformer';
+
+describe('contextTransformer', () => {
+  it('should use the targetingKey as user key', () => {
+    const got = transformContext({
+      targetingKey: 'user-key',
+    } as EvaluationContext);
+    const want: GoFeatureFlagUser = {
+      key: 'user-key',
+      anonymous: false,
+      custom: {},
+    };
+    expect(got).toEqual(want);
+  });
+
+  it('should specify the anonymous field base on attributes', () => {
+    const got = transformContext({
+      targetingKey: 'user-key',
+      anonymous: true,
+    } as EvaluationContext);
+    const want: GoFeatureFlagUser = {
+      key: 'user-key',
+      anonymous: true,
+      custom: {},
+    };
+    expect(got).toEqual(want);
+  });
+
+  it('should hash the context as key if no targetingKey provided', () => {
+    const got = transformContext({
+      anonymous: true,
+      firstname: 'John',
+      lastname: 'Doe',
+      email: '[email protected]',
+    } as EvaluationContext);
+
+    const want: GoFeatureFlagUser = {
+      key: 'dd3027562879ff6857cc6b8b88ced570546d7c0c',
+      anonymous: true,
+      custom: {
+        firstname: 'John',
+        lastname: 'Doe',
+        email: '[email protected]',
+      },
+    };
+    expect(got).toEqual(want);
+  });
+  it('should fill custom fields if extra field are present', () => {
+    const got = transformContext({
+      targetingKey: 'user-key',
+      anonymous: true,
+      firstname: 'John',
+      lastname: 'Doe',
+      email: '[email protected]',
+    } as EvaluationContext);
+
+    const want: GoFeatureFlagUser = {
+      key: 'user-key',
+      anonymous: true,
+      custom: {
+        firstname: 'John',
+        lastname: 'Doe',
+        email: '[email protected]',
+      },
+    };
+    expect(got).toEqual(want);
+  });
+});

libs/providers/go-feature-flag/src/lib/context-transformer.ts

@@ -0,0 +1,37 @@
+import { EvaluationContext } from '@openfeature/nodejs-sdk';
+import { sha1 } from 'object-hash';
+import { GoFeatureFlagUser } from './model';
+
+/**
+ * transformContext takes the raw OpenFeature context returns a GoFeatureFlagUser.
+ * @param context - the context used for flag evaluation.
+ * @returns {GoFeatureFlagUser} the user against who we will evaluate the flag.
+ */
+export function transformContext(
+  context: EvaluationContext
+): GoFeatureFlagUser {
+  const { targetingKey, ...attributes } = context;
+
+  // If we don't have a targetingKey we are using a hash of the object to build
+  // a consistent key. If for some reason it fails we are using a constant string
+  const key = targetingKey || sha1(context) || 'anonymous';
+
+  // Handle the special case of the anonymous field
+  let anonymous = false;
+  if (
+    attributes !== undefined &&
+    attributes !== null &&
+    'anonymous' in attributes
+  ) {
+    if (typeof attributes['anonymous'] === 'boolean') {
+      anonymous = attributes['anonymous'];
+    }
+    delete attributes['anonymous'];
+  }
+
+  return {
+    key,
+    anonymous,
+    custom: attributes,
+  };
+}