Migrating JavaScript

The JavaScript components have been totally rewritten in Bootstrap 4. Everything is now coded in ES6 and compiled with Babel, which makes it easier and faster to use. On the component side, the biggest difference is the Tooltips component. The Tooltip is now dependant on an external library called Tether, which you can download from:

http://github.hubspot.com/tether/ .

If you are using Tooltips, make sure you include this library in your template. The actual markup looks to be the same for calling a Tooltip but you must include the new library when migrating from version 3 to 4.