add optional encryption context to allow accessing context in eem rule function

Author: Joshua Lamke

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "aws-lambda-stream",
-  "version": "1.1.4",
+  "version": "1.1.5",
   "description": "Create stream processors with AWS Lambda functions.",
   "keywords": [
     "aws",

package.json

@@ -165,8 +165,8 @@ export const encryptData = ({
   masterKeyAlias = process.env.MASTER_KEY_ALIAS,
   regions = (process.env.KMS_REGIONS && process.env.KMS_REGIONS.split(',')),
   AES = true,
-} = {}) => async (data) => {
-  const eemMetadata = typeof eem === 'function' ? eem(data) : eem;
+} = {}) => async (data, ctx = {}) => {
+  const eemMetadata = typeof eem === 'function' ? eem(data, ctx) : eem;
   const result = await encryptObject(data, {
     masterKeyAlias,
     regions,

src/utils/encryption.js

@@ -266,14 +266,22 @@ describe('utils/encryption.js', () => {
             ...uow.event.thing,
             discriminator: 'thing',
             timestamp: uow.event.timestamp,
+          }, {
+            event: {
+              eem: {
+                fields: [
+                  'description',
+                ],
+              },
+            },
           })),
         }),
-        eem: (data) => {
+        eem: (data, ctx) => {
           if (data.discriminator === 'thing') {
             return {
               fields: [
                 'name',
-                'description',
+                ...ctx.event.eem.fields,
               ],
             };
           } else {