add the old snippet md files

old_snippets/measuring-node-js-fn-performance.md

@@ -0,0 +1,24 @@
+---
+title: "measuring node.js function performance"
+date: 2021-08-23T10:42:01+02:00
+draft: false
+snippet_types:
+- js
+- node-js
+---
+
+How fast is that new function?
+
+```diff
+ import { xx } from 'xx';
++import { performance } from 'perf_hooks';
+@@ -160,7 +161,10 @@ const userSessionMiddleware = async (req: XRequest, res: ExpressResponse, ne
++        var t0 = performance.now();
+         req.isBot = headersIndicateBot(req.headers);
++        var t1 = performance.now();
++        console.log('Took', (t1 - t0).toFixed(4), 'milliseconds to calculate is bot');
+```
+
+
+source:
+https://www.sitepoint.com/measuring-javascript-functions-performance/