Express - Import

Import Module

To make objects available outside of a module you just need to expose them as additional properties on the exports object.

1 Create square.js that exports methods.

exports.area = function(width) { return width * width; };
exports.perimeter = function(width) { return 4 * width; };

2 Import this on express app.js

const square = require('./square'); // Here we require() the name of the file without the (optional) .js file extension
console.log('The area of a square with a width of 4 is ' + square.area(4));

3 Result

Import Module 2

If you want to export a complete object in one assignment instead of building it one property at a time, assign it to module.exports

module.exports = {
  area: function(width) {
    return width * width;
  },

  perimeter: function(width) {
    return 4 * width;
  }
};

REF

https://developer.mozilla.org/en-US/docs/Learn/Server-side/Express_Nodejs/Introduction