CODEWITHSUNDEEP
node.js
sander
sander

Reputation: 1654

require('name')() vs requires ('name');

Saw this style of import on Github and was wondering why it is used? What's the deal with the () in the end?

const logger = require('pino')()

vs

const logger = require('pino');

Upvotes: 0

Views: 429

Answers (2)

freakish
freakish

Reputation: 56467

const logger = require('pino')();

is equivalent to

const loggerFn = require('pino');
const logger = loggerFn();

Does this help?

Let me give a more concrete example. Consider

foo.js

module.exports = function() {
    return 1;
};

and now in some other module

const fooFn = require('foo');
// fooFn is our defined function
const foo = fooFn();
// foo is 1

versus

const foo = require('foo')();
// foo is 1

which is equivalent.

So basically with pino package when you require('pino') you get a function which you then have to call. That's how the package was designed.

Upvotes: 2

Stephen
Stephen

Reputation: 406

To answer your question, you just need to understand what require does. When require is called, NodeJS returns the value of module.exports in the module you are requesting. In the case of pino, module.exports is equal to a function, so when you add the parenthesis to the end of the require statement, you are simply calling the function returned by require.

Upvotes: 1

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