benchmark script

package.json

@@ -15,6 +15,7 @@
   "license": "MIT",
   "dependencies": {},
   "devDependencies": {
+    "benchmark": "^2.1.4",
     "chalk": "1.1.3",
     "eslint": "^5.9.0",
     "mime-db": "^1.37.0",
@@ -27,6 +28,7 @@
   "scripts": {
     "prepare": "node src/build.js && runmd --output README.md src/README_js.md",
     "release": "standard-version",
+    "benchmark": "node src/benchmark.js",
     "md": "runmd --watch --output README.md src/README_js.md",
     "test": "mocha src/test.js"
   },

src/benchmark.js

@@ -0,0 +1,26 @@
+const Benchmark = require('benchmark');
+const mime = require('..');
+const mimeLite = require('../lite');
+
+const suite = new Benchmark.Suite();
+
+const extensions = Object.keys(mime._types);
+let idx = 0;
+
+suite
+  .add('mime.getType',
+    function() {
+      mime.getType(extensions[idx++]);
+      if (idx >= extensions.length) idx = 0;
+    }
+  )
+  .add('mimeLite.getType',
+    function() {
+      mimeLite.getType(extensions[idx++]);
+      if (idx >= extensions.length) idx = 0;
+    }
+  )
+  .on('cycle', function(event) {
+    console.log(String(event.target));
+  })
+  .run();