confusion around the arrow function callback in readFile (step 2.5)

[jsms90]

Confusion around the callback in arrow function in

readFile(filePath, (error, file) => {
  // code here
})

Add to mentor walkthrough notes:

• Clarify that readFile takes 2 arguments. The second argument is a callback function. We are defining that function & using the error-first pattern.
• Re-write this line using ES5 syntax i.e. readFile(filePath, function(error, file) {}), which students are more familiar with. Comment out the ES5 version and leave it directly above the ES6 version for comparison.