diff --git a/CHANGELOG.md b/CHANGELOG.md
index 448fcfc5..561d9f61 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+## [5.1.5](https://github.com/segmentio/typewriter/compare/5.1.4...5.1.5) (2019-01-29)
+
+
+### Bug Fixes
+
+* optional message parameter in JS clients ([#47](https://github.com/segmentio/typewriter/issues/47)) ([177069d](https://github.com/segmentio/typewriter/commit/177069d))
+
+
+
 ## [5.1.4](https://github.com/segmentio/typewriter/compare/5.1.3...5.1.4) (2019-01-25)
 
 
diff --git a/examples/gen-ios/objectivec/TypewriterExample/Analytics/SEGKicksAppAnalytics.m b/examples/gen-ios/objectivec/TypewriterExample/Analytics/SEGKicksAppAnalytics.m
index ae9a61c6..a31d8949 100644
--- a/examples/gen-ios/objectivec/TypewriterExample/Analytics/SEGKicksAppAnalytics.m
+++ b/examples/gen-ios/objectivec/TypewriterExample/Analytics/SEGKicksAppAnalytics.m
@@ -15,7 +15,7 @@ static id NSNullify(id _Nullable x) {
     NSDictionary<NSString *, id> *typewriterContext = @{
                                                         @"typewriter": @{
                                                                 @"name": @"gen-ios",
-                                                                @"version": @"5.1.4"
+                                                                @"version": @"5.1.5"
                                                                 }
                                                         };
     NSMutableDictionary *context = [NSMutableDictionary dictionaryWithCapacity:customContext.count + typewriterContext.count];
diff --git a/examples/gen-js/js/analytics/generated/index.d.ts b/examples/gen-js/js/analytics/generated/index.d.ts
index 09b3b528..ed159c69 100644
--- a/examples/gen-js/js/analytics/generated/index.d.ts
+++ b/examples/gen-js/js/analytics/generated/index.d.ts
@@ -44,19 +44,19 @@ export default class Analytics {
   constructor(analytics: any);
 
   feedViewed(
-    message?: FeedViewed,
+    props?: FeedViewed,
     options?: SegmentOptions,
     callback?: AnalyticsJSCallback
   ): void;
 
   photoViewed(
-    message?: PhotoViewed,
+    props?: PhotoViewed,
     options?: SegmentOptions,
     callback?: AnalyticsJSCallback
   ): void;
 
   profileViewed(
-    message?: ProfileViewed,
+    props?: ProfileViewed,
     options?: SegmentOptions,
     callback?: AnalyticsJSCallback
   ): void;
diff --git a/examples/gen-js/js/analytics/generated/index.js b/examples/gen-js/js/analytics/generated/index.js
index e2d97278..0aabbb96 100644
--- a/examples/gen-js/js/analytics/generated/index.js
+++ b/examples/gen-js/js/analytics/generated/index.js
@@ -3,7 +3,7 @@ const genOptions = (context = {}) => ({
     ...context,
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   }
 });
diff --git a/examples/gen-js/node/analytics/generated/index.js b/examples/gen-js/node/analytics/generated/index.js
index 4a6cf989..3ecc6029 100644
--- a/examples/gen-js/node/analytics/generated/index.js
+++ b/examples/gen-js/node/analytics/generated/index.js
@@ -4,7 +4,7 @@ const genOptions = (context = {}) => ({
   context: Object.assign({}, context, {
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   })
 });
diff --git a/examples/gen-js/ts/analytics/generated/index.d.ts b/examples/gen-js/ts/analytics/generated/index.d.ts
index 09b3b528..ed159c69 100644
--- a/examples/gen-js/ts/analytics/generated/index.d.ts
+++ b/examples/gen-js/ts/analytics/generated/index.d.ts
@@ -44,19 +44,19 @@ export default class Analytics {
   constructor(analytics: any);
 
   feedViewed(
-    message?: FeedViewed,
+    props?: FeedViewed,
     options?: SegmentOptions,
     callback?: AnalyticsJSCallback
   ): void;
 
   photoViewed(
-    message?: PhotoViewed,
+    props?: PhotoViewed,
     options?: SegmentOptions,
     callback?: AnalyticsJSCallback
   ): void;
 
   profileViewed(
-    message?: ProfileViewed,
+    props?: ProfileViewed,
     options?: SegmentOptions,
     callback?: AnalyticsJSCallback
   ): void;
diff --git a/examples/gen-js/ts/analytics/generated/index.js b/examples/gen-js/ts/analytics/generated/index.js
index e2d97278..0aabbb96 100644
--- a/examples/gen-js/ts/analytics/generated/index.js
+++ b/examples/gen-js/ts/analytics/generated/index.js
@@ -3,7 +3,7 @@ const genOptions = (context = {}) => ({
     ...context,
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   }
 });
diff --git a/package.json b/package.json
index b3c9b376..4f2a4791 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "typewriter",
-  "version": "5.1.4",
+  "version": "5.1.5",
   "description": "A compiler for generating strongly typed analytics clients from JSON Schema",
   "keywords": [
     "analytics",
diff --git a/tests/commands/gen-ios/__snapshots__/SEGTestTrackingPlanAnalytics.m b/tests/commands/gen-ios/__snapshots__/SEGTestTrackingPlanAnalytics.m
index 8ffb4c92..228e03cd 100644
--- a/tests/commands/gen-ios/__snapshots__/SEGTestTrackingPlanAnalytics.m
+++ b/tests/commands/gen-ios/__snapshots__/SEGTestTrackingPlanAnalytics.m
@@ -15,7 +15,7 @@ static id NSNullify(id _Nullable x) {
     NSDictionary<NSString *, id> *typewriterContext = @{
                                                         @"typewriter": @{
                                                                 @"name": @"gen-ios",
-                                                                @"version": @"5.1.4"
+                                                                @"version": @"5.1.5"
                                                                 }
                                                         };
     NSMutableDictionary *context = [NSMutableDictionary dictionaryWithCapacity:customContext.count + typewriterContext.count];
diff --git a/tests/commands/gen-js/__snapshots__/index.amd.js b/tests/commands/gen-js/__snapshots__/index.amd.js
index 90cd55c7..83b4649c 100644
--- a/tests/commands/gen-js/__snapshots__/index.amd.js
+++ b/tests/commands/gen-js/__snapshots__/index.amd.js
@@ -6,7 +6,7 @@ define(["require", "exports"], function(require, exports) {
       ...context,
       typewriter: {
         name: "gen-js",
-        version: "5.1.4"
+        version: "5.1.5"
       }
     }
   });
diff --git a/tests/commands/gen-js/__snapshots__/index.es5.js b/tests/commands/gen-js/__snapshots__/index.es5.js
index 92d217dd..1afbe42a 100644
--- a/tests/commands/gen-js/__snapshots__/index.es5.js
+++ b/tests/commands/gen-js/__snapshots__/index.es5.js
@@ -23,7 +23,7 @@ var genOptions = function(context) {
     context: __assign({}, context, {
       typewriter: {
         name: "gen-js",
-        version: "5.1.4"
+        version: "5.1.5"
       }
     })
   };
diff --git a/tests/commands/gen-js/__snapshots__/index.es5.node.js b/tests/commands/gen-js/__snapshots__/index.es5.node.js
index cbb2e7b2..6c6bc2b4 100644
--- a/tests/commands/gen-js/__snapshots__/index.es5.node.js
+++ b/tests/commands/gen-js/__snapshots__/index.es5.node.js
@@ -23,7 +23,7 @@ var genOptions = function(context) {
     context: __assign({}, context, {
       typewriter: {
         name: "gen-js",
-        version: "5.1.4"
+        version: "5.1.5"
       }
     })
   };
diff --git a/tests/commands/gen-js/__snapshots__/index.js b/tests/commands/gen-js/__snapshots__/index.js
index b33e8846..665dbc3d 100644
--- a/tests/commands/gen-js/__snapshots__/index.js
+++ b/tests/commands/gen-js/__snapshots__/index.js
@@ -3,7 +3,7 @@ const genOptions = (context = {}) => ({
     ...context,
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   }
 });
diff --git a/tests/commands/gen-js/__snapshots__/index.node.js b/tests/commands/gen-js/__snapshots__/index.node.js
index fa04d4be..7172e448 100644
--- a/tests/commands/gen-js/__snapshots__/index.node.js
+++ b/tests/commands/gen-js/__snapshots__/index.node.js
@@ -4,7 +4,7 @@ const genOptions = (context = {}) => ({
   context: Object.assign({}, context, {
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   })
 });
diff --git a/tests/commands/gen-js/__snapshots__/index.prod.js b/tests/commands/gen-js/__snapshots__/index.prod.js
index 2356029a..8a983eb2 100644
--- a/tests/commands/gen-js/__snapshots__/index.prod.js
+++ b/tests/commands/gen-js/__snapshots__/index.prod.js
@@ -3,7 +3,7 @@ const genOptions = (context = {}) => ({
     ...context,
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   }
 });
diff --git a/tests/commands/gen-js/__snapshots__/index.prod.node.js b/tests/commands/gen-js/__snapshots__/index.prod.node.js
index 2333f26b..21c3cba7 100644
--- a/tests/commands/gen-js/__snapshots__/index.prod.node.js
+++ b/tests/commands/gen-js/__snapshots__/index.prod.node.js
@@ -4,7 +4,7 @@ const genOptions = (context = {}) => ({
   context: Object.assign({}, context, {
     typewriter: {
       name: "gen-js",
-      version: "5.1.4"
+      version: "5.1.5"
     }
   })
 });
diff --git a/tests/commands/gen-js/__snapshots__/index.system.js b/tests/commands/gen-js/__snapshots__/index.system.js
index 91f23620..747c8a8e 100644
--- a/tests/commands/gen-js/__snapshots__/index.system.js
+++ b/tests/commands/gen-js/__snapshots__/index.system.js
@@ -10,7 +10,7 @@ System.register([], function(exports_1, context_1) {
           ...context,
           typewriter: {
             name: "gen-js",
-            version: "5.1.4"
+            version: "5.1.5"
           }
         }
       });
diff --git a/tests/commands/gen-js/__snapshots__/index.umd.js b/tests/commands/gen-js/__snapshots__/index.umd.js
index 9bb7b8a9..c476fd72 100644
--- a/tests/commands/gen-js/__snapshots__/index.umd.js
+++ b/tests/commands/gen-js/__snapshots__/index.umd.js
@@ -13,7 +13,7 @@
       ...context,
       typewriter: {
         name: "gen-js",
-        version: "5.1.4"
+        version: "5.1.5"
       }
     }
   });