Does Node run all the code inside required modules?

Question

Are node modules run when they are required?

For example: You have a file foo.js that contains some code and some exports.

When I import the file by running the

Answer 1

Before exporting the content that are visible outside of your module, if there is same code that can be execute it it execute but the content that are export like a class will be execute in the code that import it.

For example, if I have this code

console.log("foo.js")
module.exports = {
     Person: function(){}   
} 

the console.log will be execute when you require it.