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Another method other than a constructor in a JavaScript class?
In this artcle we are going to learn another method other than a constructor in a JavaScript class with suitable examples in JavaScript
The Constructor is used to create and initialize an instance of a class i.e., object. The constructor's job is to build a new object and set values for any attributes that already exist on the object. Every class has a default constructor. If we don’t provide our own constructor, then the default constructor will be incoked.
Let’s understand this concept in a better way with the help of suitable examples further in this article.
Syntax
The syntax for a constructor is −
Constructor(); // No parameters Constructor(param1); //One parameter constructor Constructor(param1,param2,…,paramN) // N-parameter constructor.
Param1, param2, …paramN are the parameters passed to the constructor.
Example 1
This is an example program to write a method other than a constructor.
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Another method other than a constructor in a JavaScript class</title> </head> <body style="text-align: center ;"> <p> Another method other than a constructor in a JavaScript class </p> <p id="method"></p> <script> class Person { constructor(name){ this.name = name; } PersonName() { return 'The person name is : '+this.name; } } person_1 = new Person("Raghu"); document.getElementById("method").innerHTML = person_1.PersonName(); </script> </body> </html>
On executing the above code, the below output is generated.
Example 2
This is an example program to illustrate the usage of method other than a constructor. Instead of using the default constructor for initialization, we used a user-defined method called PersonDetails().
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Another method other than a constructor in a JavaScript class</title> </head> <body style="text-align: center ;"> <p> Another method other than a constructor in a JavaScript class </p> <p id="method"></p> <script> class Person { constructor(name, EmployeeID, designation) { this.name = name; this.EmployeeID = EmployeeID; this.designation = designation; } PersonDetails() { return this.name + " has the designation : " + this.designation; } } person_1 = new Person("Rajesh", "10023", "Software Engineer"); document.getElementById("method").innerHTML = person_1.PersonDetails(); </script> </body> </html>
On executing the above code, the below output is generated.
Example 3
In the following example, rather than using the default method constructor() the properties were actually initialized in a user given method called "anotherMet()". Through this method, the actual result is executed in the output as shown.
<html> <body> <p id="method"></p> <script> class Company { constructor(branch) { this.name = branch; } anotherMet(x) { return x + " is the head of " + this.name; } } myComp = new Company("Microsoft."); document.getElementById("method").innerHTML = myComp.anotherMet("Bill gates"); </script> </body> </html>
On executing the above code, the below output is generated.