The constructor method in JavaScript is used to create and initialize object created within a class. If a constructor method is not added, then a default constructor should be used.
Note − Only one occurrence of a constructor method is allowed in a class. More than one throws an error.
Example
You can try to run the following code to learn how to implement a constructor method
Live Demo
<html> <body> <script> class Department { constructor() { this.name = "Department"; } } class Employee extends Department { constructor() { super(); } } class Company {} Object.setPrototypeOf(Employee.prototype, Company.prototype); document.write("<br>"+Object.getPrototypeOf(Employee.prototype) === Department.prototype); let myInstance = new Employee(); document.write("<br>"+myInstance.name); </script> </body> </html>