Node.js Best Practices — Using Modern Features

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Node.js is a popular runtime to write apps. These apps are often production quality apps that are used by many people. To make maintaining them easier, we’ve to set some guidelines for people to follow.

In this article, we’ll look at some modern JavaScript features that we should use to create code that’s clean and easy to maintain.

Prefer const over let. Ditch the var

var is an outdated keyword for creating variables that should never be used again. The scope is inconsistent unlike let and const . var is function scoped, so that it can be accessed from outside blocks and create potential issues with our code.

let and const are blocked scoped so they can’t be accessed outside a block. const prevents reassignment of the constant to another value.

For example, if we have the following code:

var callbacks = [];
(function() {
  for (var i = 0; i < 5; i++) {
    callbacks.push( function() { return i; } );
  }
})();
console.log(callbacks.map( function(cb) { return cb(); } ));

Then we’ll see [ 5, 5, 5, 5, 5 ] as the value of callbacks.map( function(cb) { return cb(); } ).