add benchmark.js benchmark (for #20)

ensures statistical significance

bench/basic.js

@@ -0,0 +1,14 @@
+var random = require('crypto').pseudoRandomBytes
+
+var b64 = require('../')
+var data = random(1e6).toString('base64')
+var start = Date.now()
+var raw = b64.toByteArray(data)
+var middle = Date.now()
+data = b64.fromByteArray(raw)
+var end = Date.now()
+
+console.log('decode ms, decode ops/ms, encode ms, encode ops/ms')
+console.log(
+  middle - start, data.length / (middle - start),
+  end - middle, data.length / (end - middle))

bench/bench.js

@@ -1,14 +1,22 @@
-var random = require('crypto').pseudoRandomBytes
+var base64 = require('../')
+var benchmark = require('benchmark')
 
-var b64 = require('../')
+var suite = new benchmark.Suite()
+var random = require('crypto').pseudoRandomBytes
 var data = random(1e6).toString('base64')
-var start = Date.now()
-var raw = b64.toByteArray(data)
-var middle = Date.now()
-data = b64.fromByteArray(raw)
-var end = Date.now()
+var raw = base64.toByteArray(data)
 
-console.log('decode ms, decode ops/ms, encode ms, encode ops/ms')
-console.log(
-	middle - start, data.length / (middle - start),
-	end - middle, data.length / (end - middle))
+suite
+  .add('base64.toByteArray() (decode)', function () {
+    var raw2 = base64.toByteArray(data) // eslint-disable-line no-unused-vars
+  })
+  .add('base64.fromByteArray() (encode)', function () {
+    var data2 = base64.fromByteArray(raw) // eslint-disable-line no-unused-vars
+  })
+  .on('error', function (event) {
+    console.error(event.target.error.stack)
+  })
+  .on('cycle', function (event) {
+    console.log(String(event.target))
+  })
+  .run({ async: true })

package.json

@@ -14,6 +14,7 @@
   "license": "MIT",
   "dependencies": {},
   "devDependencies": {
+    "benchmark": "^2.1.0",
     "standard": "^6.0.5",
     "tape": "4.x"
   }