Add createDirIfNotExists snippet

snippets/createDirIfNotExists.md

@@ -0,0 +1,14 @@
+### createDirIfNotExists
+
+Creates a directory, if it does not exist.
+
+Use `fs.existsSync()` to check if the directory exists, `fs.mkdirSync()` to create it.
+
+```js
+const fs = require('fs');
+const createDirIfNotExists = dir => !fs.existsSync(dir) ? fs.mkdirSync(dir) : undefined;
+```
+
+```js
+createDirIfNotExists('test'); // creates the directory 'test', if it doesn't exist
+```