Subject of the issue

From version 8 and above gridstack produces a weird, hard to debug "maximum call stack size exceeded" error and crashes the whole page when cellHeight is set with "rem". It is working properly with v7

Steps to reproduce

You can reproduce it in with the gridstack repo.

In the Gridstack repo go to: angular -> projects -> demo -> src -> app -> app.component.ts
Add for example: cellHeight: '23rem' to gridOptions in line # 36
Run the app locally, select the proper demo and try to drag&drop one of the grid items