## Give me the code

### Instructions

Create a `jsFileOnly` function that takes an array of filenames (strings) and
only keeps those that are ending with `.js`

**Example:**

```js
const result = jsFileOnly([
  'essay.docx',
  'index.html',
  'info.txt',
  'lib.js',
  'README.md',
  'script.js',
])

console.log(result) // ['lib.js', 'script.js']
```