[minor] add performance benchmarks

package.json

@@ -8,7 +8,8 @@
     "mocha": "^6.2.0"
   },
   "scripts": {
-    "test": "echo \"Running Mocha Tests\" && mocha ./tests/index.js"
+    "test": "echo \"Running Mocha Tests\" && mocha ./tests/index.js",
+    "bench": "echo \"Running Performance Benchmark\" && node ./tests/performance.js"
   },
   "repository": {
     "type": "git",

tests/benchmarker.js

@@ -0,0 +1,18 @@
+exports.bench = function (f) {
+  let ops = 0;
+  const startMs = Date.now();
+  const end = startMs + 1000;
+  while(Date.now() < end) {
+    f();
+    ops++;
+  }
+  return ops;
+};
+
+exports.bench10 = function(f) {
+  let ops = 0;
+  for(let i = 0; i < 10; i++) {
+    ops += exports.bench(f);
+  }
+  return ops / 10;
+}

tests/performance.js

@@ -0,0 +1,93 @@
+const benchmarker = require('./benchmarker');
+const diffler = require('../src');
+
+const suite = function() {
+  const testObjectA = {
+    "id": 157538,
+    "date": "2017-07-21T10:30:34",
+    "date_gmt": "2017-07-21T17:30:34",
+    "guid": {
+      "rendered": "https://www.sitepoint.com/?p=157538"
+    },
+    "modified": "2017-07-23T21:56:35",
+    "modified_gmt": "2017-07-24T04:56:35",
+    "slug": "why-the-iot-threatens-your-wordpress-site-and-how-to-fix-it",
+    "status": "publish",
+    "type": "post",
+    "link": "https://www.sitepoint.com/why-the-iot-threatens-your-wordpress-site-and-how-to-fix-it/",
+    "title": {
+      "rendered": "Why the IoT Threatens Your WordPress Site (and How to Fix It)"
+    },
+    "content": {
+    },
+    "excerpt": {
+    },
+    "author": 72546,
+    "featured_media": 157542,
+    "comment_status": "open",
+    "ping_status": "closed",
+    "sticky": false,
+    "template": "",
+    "format": "standard",
+    "meta": [],
+    "categories": [
+      6132
+    ],
+    "tags": [
+      1798,
+      6298
+    ]
+  };
+  const testObjectB = {
+    "id": 157538,
+    "date": "2017-07-21T10:30:34",
+    "date_gmt": "2017-07-21T17:30:34",
+    "guid": {
+      "rendered": "https://www.sitepoint.com/?p=157538"
+    },
+    "modified": "2017-07-23T21:56:35",
+    "modified_gmt": "2017-07-24T04:56:35",
+    "slug": "why-the-iot-threatens-your-wordpress-site-and-how-to-fix-it",
+    "status": "publish",
+    "type": "post",
+    "link": "https://www.sitepoint.com/why-the-iot-threatens-your-wordpress-site-and-how-to-fix-it/",
+    "title": {
+      "rendered": "Why the IoT Threatens Your WordPress Site (and How to Fix It)"
+    },
+    "content": {
+    },
+    "excerpt": {
+    },
+    "author": 72546,
+    "featured_media": 157542,
+    "comment_status": "open",
+    "ping_status": "closed",
+    "sticky": false,
+    "template": "",
+    "format": "standard",
+    "meta": [],
+    "categories": [
+      6132
+    ],
+    "tags": [
+      1798,
+      6298
+    ]
+  };
+  diffler(testObjectA, testObjectB);
+}
+
+const ops = benchmarker.bench10(suite);
+const benchmark = 236941; // update value to set new benchmark
+console.info(`Executed ${ops} ops/s`);
+const diff = Math.round(100 - ((benchmark / ops) * 100));
+
+if (diff === 0) {
+  console.log('Bench complete: Code hasn\'t changed.');
+  return;
+} else if (diff < -10) {
+  console.error(`Bench complete: Code ran ${Math.abs(diff)}% slower, it's time to do something.`);
+  return;
+}
+const message = diff > 0 ? 'faster': 'slower';
+console.info(`Bench complete: Code ran ${Math.abs(diff)}% ${message} than benchmark.`);