How to instantiate a javascript class in another js file?

Solution 1:

It depends on what environment you're running in. In a web browser you simply need to make sure that file1.js is loaded before file2.js:

<script src="file1.js"></script>
<script src="file2.js"></script>

In node.js, the recommended way is to make file1 a module then you can load it with the require function:

require('path/to/file1.js');

It's also possible to use node's module style in HTML using the require.js library.

Solution 2:

// Create Customer class as follows:
export default class Customer {
   getName() {
     return 'stackoverflow';
   }
}

// Import the class 
// no need for .js extension in path cos it gets inferred automatically
import Customer from './path/to/Customer'; 
// OR
const Customer = require('./path/to/Customer') 

// Use the class
var customer = new Customer();
var name = customer.getName();

Solution 3:

You can export your methods to access from other files like this:

file1.js

var name = "Jhon";
exports.getName = function() {
  return name;
}

file2.js

var instance = require('./file1.js');
var name = instance.getName();