JavaScript constructor

In JavaScript, a constructor is a function that is used to create and initialize an object created with the new keyword. When the new keyword is used with this function, a new object is created with the properties.

JavaScript constructor example

Simple HTML example code.

<!DOCTYPE html>
<html>

<body>
  <script >
   function Person(name, age) {
      this.name = name;
      this.age = age;
    }

    let p1 = new Person('John', 30);
    console.log(p1)
    console.log(typeof(p1))

  </script>
</body>
</html>

Output:

Constructors can also be defined using class syntax, introduced in ECMAScript 2015 (ES6):

class Person {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }
}

let p1 = new Person('John', 30);

In this case, the Person class has a constructor method that is called when a new object is created with the new keyword. The constructor initializes the name and age properties of the new object.

Do comment if you have any doubts or suggestions on this JS constructor topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version

JavaScript constructor