Bob Massarczyk thinks this is interesting: In JavaScript, function arguments are references to the actual data. From 3. Functional Programming with JavaScript from Learning React, 1st Edition by Alex Banks, Eve Porcello Publisher: O'Reilly Media, Inc. Released: May 2017 Note No, only if those arguments are non-primitive data types like objects and arrays. Primitive data types like strings, numbers and boolean are copy by value, not reference. Share this highlight http://www.safaribooksonline.com/a/learning-react-1st/9447422/ Twitter Facebook Google Plus Email Get Instant Access Now Start a Free Trial Have an account? Sign in. Minimise Unlock the rest of Learning React, 1st Edition and 30,000 other books and videos By clicking this box, you confirm that you have read and agree to the terms and conditions of our Membership Agreement, and you understand that when your trial period ends, you will be required to provide billing information if you wish to continue using the service. Unlock the rest of this book Start a Free 10-Day Trial loading Learn about Safari for Business Have an account? Sign in.