More consistent use of ES6 syntax

[bobbysebolao]

Well done for using ES6 syntax in places; you've used arrow functions pretty consistently, with only one exception in validate.js where you've used the ES5 function keyword instead.

There are 9 places where you've used the var keyword to declare variables in your project. It's not best practice to declare variables this way, you should use let or const, depending on whether you need to reassign the variable's value or not.

Also, when you return a single statement from an arrow function, you don't need the curly brackets around the return statement. You can tweak your server function in server.js with this in mind.