require()

require()

To make use of the exported module and the behavior we define within it, we import the module into another file. In Node.js, use the require() function to import modules.

For instance, say we want the module to control the menu’s data and behavior, and we want a separate file to handle placing an order. We would create a separate file order.js and import the Menu module from menu.js to order.js using require(). require() takes a file path argument pointing to the original module file.

In order.js we would write:

const Menu = require('./menu.js');

function placeOrder() {
  console.log('My order is: ' + Menu.specialty);
}

placeOrder();

 

 

We now have the entire behavior of Menu available in order.js. Here, we notice:

1. In order.js we import the module by creating a const variable called Menu and setting it equal to the value of the require() function. We can set the name of this variable to anything we like, such as menuItems.
2. require() is a JavaScript function that loads a module. It’s argument is the file path of the module: ./menu.js. With require(), the .js extension is optional and will be assumed if it is not included.
3. The placeOrder() function then uses the Menu module. By calling Menu.specialty, we access the property specialty defined in the Menu module.

Taking a closer look, the pattern to import a module is:

1. Import the module with require() and assign it to a local variable.
2. Use the module and its properties within a program.

 

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const Airplane = require('./1-airplane.js');

function displayAirplane() {
  console.log(Airplane.myAirplane);
}

displayAirplane();