JavaScript Q&A Logo
JavaScript Q&A Part of the Q&A Topic Learning Network
Real Questions. Clear Answers.
Ask any question about JavaScript here... and get an instant response.
Q&A Balloon Q&A Logo
Post this Question & Answer:

How is the rest operator used in JavaScript functions?

Asked on Jul 06, 2025

Answer

The rest operator in JavaScript functions allows you to represent an indefinite number of arguments as an array. It's useful for handling function parameters when the number of arguments is not fixed.
<!-- BEGIN COPY / PASTE -->
        function sum(...numbers) {
            return numbers.reduce((total, num) => total + num, 0);
        }

        console.log(sum(1, 2, 3, 4)); // Output: 10
        <!-- END COPY / PASTE -->
Additional Comment:
  • The rest operator is represented by three dots "..." followed by a variable name.
  • In the example, "numbers" is an array containing all the arguments passed to the "sum" function.
  • The "reduce" method is used to sum up all the numbers in the "numbers" array.
  • The rest operator must be the last parameter in a function's parameter list.
✅ Answered with JavaScript best practices.
← Back to All Questions

Q&A Network
Real Questions. Clear Answers.
JavaScript
Ask Questions / Get Answers about JavaScript!
Data Science
Ask Questions / Get Answers about Data Science!
Social Media Psychology
Ask Questions / Get Answers about Social Media Psychology!
CSS
Ask Questions / Get Answers about CSS!
AI Design
Ask Questions / Get Answers about AI Design!
Cybersecurity
Ask Questions / Get Answers about Cybersecurity!
MobileDev
Ask Questions / Get Answers about Mobile Developement!
Photography
Ask Questions / Get Answers about Photography!
AI Audio
Ask Questions / Get Answers about AI Audio!
Performance
Ask Questions / Get Answers about Web Vitals!
Security
Ask Questions / Get Answers about Website Security!
Creative Writing
Ask Questions / Get Answers about Creative Writing!
Analytics
Ask Questions / Get Answers about Analytics!
AI Writing
Ask Questions / Get Answers about AI Writing!
3D Design
Ask Questions / Get Answers about 3D Design!
Robotics
Ask Questions / Get Answers about Robotics!
AI Marketing
Ask Questions / Get Answers about AI Marketing!
IoT
Ask Questions / Get Answers about IoT!
Bootstrap
Ask Questions / Get Answers about Bootstrap!
Sound Design
Ask Questions / Get Answers about Sound Design!
Illustration
Ask Questions / Get Answers about Illustration!
Video Editing
Ask Questions / Get Answers about Video Editing!
Film Production
Ask Questions / Get Answers about Film Production!
AI
Ask Questions / Get Answers about AI!
Web Development
Ask Questions / Get Answers about Web Development!
SEO
Ask Questions / Get Answers about SEO!
Animation
Ask Questions / Get Answers about Animation!
DevOps
Ask Questions / Get Answers about DevOps!
Networking
Ask Questions / Get Answers about Networking!
AI Coding
Ask Questions / Get Answers about AI Coding!
Web Languages
Ask Questions / Get Answers about Web Languages!
WordPress
Ask Questions / Get Answers about WordPress!
UI/UX Design
Ask Questions / Get Answers about UI/UX Design!
AI Images
Ask Questions / Get Answers about AI Images!
Quantum
Ask Questions / Get Answers about Quantum Computing!
Digital Burnout
Ask Questions / Get Answers about Digital Burnout!
Nursing
Ask Questions / Get Answers about Nursing!
Monetization
Ask Questions / Get Answers about Ad & Monetization!
Chatbots
Ask Questions / Get Answers about Chatbots!
Podcasting
Ask Questions / Get Answers about Podcasting!
Tailwind
Ask Questions / Get Answers about Tailwind!
Business Finance
Ask Questions / Get Answers about Business Finance!
AI Business
Ask Questions / Get Answers about AI Business!
AI Video
Ask Questions / Get Answers about AI Video!
Motion Graphics
Ask Questions / Get Answers about Motion Graphics!
Web Hosting
Ask Questions / Get Answers about Hosting!
HTML
Ask Questions / Get Answers about HTML!
AI Ethics
Ask Questions / Get Answers about AI Ethics!
Graphic Design
Ask Questions / Get Answers about Graphic Design!
VR & AR
Ask Questions / Get Answers about VR & AR!
AI Education
Ask Questions / Get Answers about AI Education!
Cloud Computing
Ask Questions / Get Answers about Cloud Computing!