Merge pull request #5 from AntonBazhal/next-null

Does not override event and context when null is passed

Author: AntonBazhal

lib/handler.js

@@ -7,11 +7,11 @@ async function dispatch(middleware, state, i = 0) {
 			throw err;
 		}
 
-		if (context !== undefined) {
+		if (context !== undefined && context !== null) {
 			state.context = context;
 		}
 
-		if (event !== undefined) {
+		if (event !== undefined && event !== null) {
 			state.event = event;
 		}
 

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@alpha-lambda/handler",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Middleware pipeline for AWS Lambda handlers",
   "repository": {
     "type": "git",

package.json

@@ -212,6 +212,40 @@ describe('handler', function() {
 				});
 		});
 
+		it('middleware does not override context and event when their values are null', function() {
+			const spy = sinon.spy();
+
+			const fixture = lambdaHandler()
+				.use(function(event, context, next) {
+					return next(null, null, null);
+				})
+				.use(spy);
+
+			return fixture(testEvent, testContext)
+				.then(() => {
+					expect(spy.calledOnce).to.be.true;
+					expect(spy.firstCall.args[0]).to.equal(testEvent);
+					expect(spy.firstCall.args[1]).to.equal(testContext);
+				});
+		});
+
+		it('middleware does not override context and event when their values are undefined', function() {
+			const spy = sinon.spy();
+
+			const fixture = lambdaHandler()
+				.use(function(event, context, next) {
+					return next(null, undefined, undefined);
+				})
+				.use(spy);
+
+			return fixture(testEvent, testContext)
+				.then(() => {
+					expect(spy.calledOnce).to.be.true;
+					expect(spy.firstCall.args[0]).to.equal(testEvent);
+					expect(spy.firstCall.args[1]).to.equal(testContext);
+				});
+		});
+
 		it('middleware can override result after await next()', function() {
 			const stub = sinon.stub().returns('foo');
 			const fixture = lambdaHandler()