DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports
Events Video Library
Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
View Events Video Library
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks

UK-US Data Bridge: Join TechnologyAdvice and OneTrust as they discuss the UK extension to the EU-US Data Privacy Framework (DPF).

Migrate, Modernize and Build Java Web Apps on Azure: This live workshop will cover methods to enhance Java application development workflow.

Kubernetes in the Enterprise: The latest expert insights on scaling, serverless, Kubernetes-powered AI, cluster security, FinOps, and more.

A Guide to Continuous Integration and Deployment: Learn the fundamentals and understand the use of CI/CD in your apps.

Related

  • Practical Example of Using CSS Layer
  • Shallow and Deep Copies in JavaScript: What’s the Difference?
  • Decorators and Mixins in Lightning Web Components
  • Improving ui-select Control

Trending

  • Micro Frontends Architecture
  • Ensuring API Resilience in Spring Microservices Using Retry and Fallback Mechanisms
  • What’s New Between Java 17 and Java 21?
  • Legacy App Migration: How Discovery Phase Speeds up Project Delivery
  1. DZone
  2. Coding
  3. JavaScript
  4. How to Add a Static Member Property in a JavaScript Class

How to Add a Static Member Property in a JavaScript Class

Take a look at this quick article to learn about static member properties and how to use them in your JS code.

Dhananjay Kumar user avatar by
Dhananjay Kumar
·
Mar. 08, 19 · Tutorial
Like (2)
Save
Tweet
Share
13.7K Views

Join the DZone community and get the full member experience.

Join For Free

Recently while solving a problem, I came across a requirement to create a property in a JavaScript class, which needs to be shared by all the object instances. In the programming world, these types of properties are called Static Properties.

There are various scenarios when you need a static member property:

  • When counting the number of object instances created from a particular class.
  • When logging some information at the class level instead of object instance level, etc.

To create a static property, you should know two important things:

  1. A JavaScript class cannot have a member property. You can only create it using a constructor.
  2. Like the function constructor, a JavaScript class also has a prototype.

Well, if you are a champion of prototypes, you must have guessed the answer already. Any way, let us moAnywayard to see the implementation:

class Foo {

    constructor(goal) {
        this.goal = goal;
        Foo.prototype.objectcount++;
    }

}
Foo.prototype.objectcount = 0; 

Let us talk through the implementation of Foo class:

  1. We added a property to the Foo class prototype.
  2. Incremented it in the constructor, as the constructor would be called each time an object is created.

Essentially to create a static property member, add a property to class prototype object. Now, creating an instance of Foo class:

let f1 = new Foo(78);
console.log(f1.objectcount); // 1
let f2 = new Foo(45);
console.log(f2.objectcount)// 2
let f3 = new Foo(45);
console.log(f3.objectcount)// 2
console.log(f1.objectcount === f2.objectcount);// true 
console.log(f2.objectcount === f3.objectcount);// true 

You can see that now objectcount keeps track of the count of all the objects. It is the same for all the object instances as well, hence, it can be termed as a static member property of a JavaScript class.

I hope you find this quick tip useful.

Property (programming) JavaScript

Published at DZone with permission of Dhananjay Kumar, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

Related

  • Practical Example of Using CSS Layer
  • Shallow and Deep Copies in JavaScript: What’s the Difference?
  • Decorators and Mixins in Lightning Web Components
  • Improving ui-select Control

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Core Program
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 3343 Perimeter Hill Drive
  • Suite 100
  • Nashville, TN 37211
  • support@dzone.com

Let's be friends: