How does require work with new operator in node.js?
new-operator, node.js, require
Solution
These two versions are fundamentally different.
This one:
new (require('./file')).func('r1');
Executes the require, returning the exports of `./file` and then calling the new operator on the results .
This one:
var r2 = new require('./file').func('r2');
Invokes require as a constructor.
Let's look at a more isolated and simple example:
new Date() // creates a new date object
new (Date()) // throws a TypeError: string is not a function
Problem
Let's have a file.js with this code: ``` module.exports.func = function(txt) { this.a = 1; this.b = 2; console.log(txt, this); return this; } ``` Now we have another JS file where we do following: ``` var r1 = new (require('./file')).func('r1'); var r2 = new require('./file').func('r2'); ``` In r1 case it works as intended - r1 contains reference to the newly created object. In r2 case it does not work - r2 gets reference to module.exports from within the file.js. The intention was to create a new object by calling func() constructor. Sure, I can do it also this way which is equal to r1: ``` var r3 = require('./file'); var r4 = new r3.func('r1'); ``` However, I do not understand why r2 does not behave the same way as r1. How do the extra parenthesis around require('./file') make a difference?