[BUG] Javascript syntax hihglight doesn't work in 5.65.19

[jousepo]

After update dependencies in my project, codemirror from 5.65.18 to 5.65.19, javascript highlight syntax stop working

[marijnh]

Your dependency tree contains duplicated versions of some packages. If you're using yarn, switch to npm, which is a lot less broken. Or remove your package lock and reinstall if you really want to stick with yarn.