Improve error message for null/undefined to res.status

closes #2795
closes #2797
closes #3111

History.md

@@ -2,6 +2,7 @@ unreleased
 ==========
 
   * Improve error message for non-strings to `res.sendFile`
+  * Improve error message for `null`/`undefined` to `res.status`
 
 4.16.4 / 2018-10-10
 ===================

lib/response.js

@@ -64,6 +64,10 @@ var charsetRegExp = /;\s*charset\s*=/;
  */
 
 res.status = function status(code) {
+  if (code === undefined || code === null) {
+    throw new TypeError('code argument is required to res.status')
+  }
+
   this.statusCode = code;
   return this;
 };

test/res.status.js

@@ -16,5 +16,37 @@ describe('res', function(){
       .expect('Created')
       .expect(201, done);
     })
+
+    describe('when code is undefined', function () {
+      it('should throw a TypeError', function (done) {
+        var app = express()
+
+        app.use(function (req, res) {
+          res.status(undefined).send('OK')
+        })
+
+        request(app)
+        .get('/')
+        .expect(500)
+        .expect(/TypeError: code argument is required to res.status/)
+        .end(done)
+      })
+    })
+
+    describe('when code is null', function () {
+      it('should throw a TypeError', function (done) {
+        var app = express()
+
+        app.use(function (req, res) {
+          res.status(null).send('OK')
+        })
+
+        request(app)
+        .get('/')
+        .expect(500)
+        .expect(/TypeError: code argument is required to res.status/)
+        .end(done)
+      })
+    })
   })
 })