Make error message optional when reporting

Author: rhart

README.md

@@ -117,7 +117,7 @@ Given a function that has been instrumented, revert the function to it's origina
 
 * **fn: Function** - Instrumented Function
 
-#### `StackTrace.report(message, stackframes, url)` => [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)(String)
+#### `StackTrace.report(stackframes, url, message)` => [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)(String)
 Given an an error message and Array of StackFrames, serialize and POST to given URL. Promise is resolved with response text from POST request.
 
 Example JSON POST data:

spec/stacktrace-spec.js

@@ -192,12 +192,12 @@ describe('StackTrace', function() {
             jasmine.Ajax.uninstall();
         });
 
-        it('sends POST request to given URL', function(done) {
+        it('sends POST request to given URL with a message', function(done) {
             var url = 'http://domain.ext/endpoint';
             var errorMsg = 'BOOM';
             var stackframes = [new StackFrame('fn', undefined, 'file.js', 32, 1)];
 
-            StackTrace.report(errorMsg, stackframes, url).then(callback, done.fail)['catch'](done.fail);
+            StackTrace.report(stackframes, url, errorMsg).then(callback, done.fail)['catch'](done.fail);
 
             var postRequest = jasmine.Ajax.requests.mostRecent();
             postRequest.respondWith({status: 201, contentType: 'text/plain', responseText: 'OK'});
@@ -210,13 +210,29 @@ describe('StackTrace', function() {
             }
         });
 
+        it('sends POST request to given URL without a message', function(done) {
+            var url = 'http://domain.ext/endpoint';
+            var stackframes = [new StackFrame('fn', undefined, 'file.js', 32, 1)];
+
+            StackTrace.report(stackframes, url).then(callback, done.fail)['catch'](done.fail);
+
+            var postRequest = jasmine.Ajax.requests.mostRecent();
+            postRequest.respondWith({status: 201, contentType: 'text/plain', responseText: 'OK'});
+
+            function callback() {
+                expect(postRequest.data()).toEqual({stack: stackframes});
+                expect(postRequest.method).toBe('post');
+                expect(postRequest.url).toBe(url);
+                done();
+            }
+        });
+
         it('rejects if POST request fails', function(done) {
             var url = 'http://domain.ext/endpoint';
-            var errorMsg = 'BOOM';
             var stackframes = [new StackFrame('fn', undefined, 'file.js', 32, 1)];
 
             jasmine.Ajax.stubRequest(url).andError();
-            StackTrace.report(errorMsg, stackframes, url).then(done.fail, done)['catch'](done);
+            StackTrace.report(stackframes, url).then(done.fail, done)['catch'](done);
         });
     });
 });

stacktrace.js

@@ -167,8 +167,9 @@
          *
          * @param {Array} stackframes
          * @param {String} url
+         * @param {String} errorMsg
          */
-        report: function StackTrace$$report(errorMsg, stackframes, url) {
+        report: function StackTrace$$report(stackframes, url, errorMsg) {
             return new Promise(function(resolve, reject) {
                 var req = new XMLHttpRequest();
                 req.onerror = reject;
@@ -183,7 +184,13 @@
                 };
                 req.open('post', url);
                 req.setRequestHeader('Content-Type', 'application/json');
-                req.send(JSON.stringify({message: errorMsg, stack: stackframes}));
+
+                var reportPayload = {stack: stackframes};
+                if (errorMsg != undefined) {
+                  reportPayload.message = errorMsg;
+                }
+
+                req.send(JSON.stringify(reportPayload));
             });
         }
     };