Add direct empty object tests

Author: TotalTechGeek

compiler.js

@@ -114,7 +114,9 @@ function isDeepSync (method, engine) {
   if (Array.isArray(method)) return method.every(i => isDeepSync(i, engine))
 
   if (method && typeof method === 'object') {
-    const func = Object.keys(method)[0]
+    const keys = Object.keys(method)
+    if (keys.length === 0) return true
+    const func = keys[0]
 
     const lower = method[func]
     if (!isSync(engine.methods[func])) return false

suites/plus.json

@@ -182,5 +182,17 @@
         "rule": { "+": [[1]] },
         "result": { "error": "NaN" },
         "data": null
+    },
+    {
+        "description": "Plus Operator with Single Operand, Object Input Produces NaN",
+        "rule": { "+": [{}] },
+        "result": { "error": "NaN" },
+        "data": null
+    },
+    {
+        "description": "Plus Operator with Single Operand, Direct Object Input Produces NaN",
+        "rule": { "+": {} },
+        "result": { "error": "NaN" },
+        "data": null
     }
 ]