feat: add the original function parameters to the list of arguments e…

…mitted in a failure event.

fixes nodeshift#324

lib/circuit.js

@@ -638,7 +638,7 @@ function fail (circuit, err, args, latency) {
    * @event CircuitBreaker#failure
    * @type {Error}
    */
-  circuit.emit('failure', err, latency);
+  circuit.emit('failure', err, latency, args);
   if (circuit.warmUp) return;
 
   // check stats to see if the circuit should be opened

test/test.js

@@ -795,6 +795,23 @@ test('Circuit Breaker failure event emits latency', t => {
   breaker.fire(-1).catch(noop);
 });
 
+test('Circuit Breaker failure event emits function parameters', t => {
+  t.plan(6);
+  const breaker = circuit(passFail);
+  breaker.on('failure', (result, latencyTime, args) => {
+    t.ok(args, 'third argument is the latency');
+    t.equal(Array.isArray(args), true, 'The args parameter is an array');
+    t.equal(args[0], -1, 'this is the first argument');
+    t.equal(args[1].arg1, 'arg1', 'this is the second argument object');
+    t.equal(args[1].arg2, 'arg2', 'this is the second argument object');
+    t.equal(args[2][0], '1', 'this is the third argument');
+    breaker.shutdown();
+    t.end();
+  });
+
+  breaker.fire(-1, { arg1: 'arg1', arg2: 'arg2' }, ['1', '2']).catch(noop);
+});
+
 test('Circuit Breaker timeout event emits latency', t => {
   t.plan(1);
   const breaker = circuit(slowFunction, { timeout: 10 });