fix(dom-utils): check for `el.classList` existence (closes #2713) (#2714)
fix(dom-utils): check for `el.classList` existence (closes #2713) (#2714)

* chore: prettify

* Revert "chore: prettify"

This reverts commit b444bf50b2b15a4670aeac3a0150029353225118.

* fix(dom-utils): check for `el.classList` existence

* add comment reference to issue

* Update dom.js

* make `isVisible()`, `offset()` and `position()` utils more safe

* move istanbul comments

* fix contradicting offset / function offset in position method

* Update dom.js

* Update dom.js

bootstrap-vue/bootstrap-vue,tmorehouse/bootstrap-vue,bootstrap-vue/bootstrap-vue,tmorehouse/bootstrap-vue