Wagtailcodeblock is broken in wagtail 4.2.

[lunaluxie]

When trying to use wagtailcodeblock in a streamfield, in the admin, I get the following Javascript error which prevents the streamfield from loading.

It worked fine in wagtail 4.1, but it's broken in 4.2.

Uncaught TypeError: Class constructor g cannot be invoked without 'new'
    at new CodeBlockDefinition (wagtailcodeblock.js:2:60)
    at t.value (VM90 telepath.js:1:3635)
    at VM90 telepath.js:1:3030
    at Array.map (<anonymous>)
    at t.value (VM90 telepath.js:1:3004)
    at VM90 telepath.js:1:3030
    at Array.map (<anonymous>)
    at t.value (VM90 telepath.js:1:3004)
    at VM90 telepath.js:1:3030
    at Array.map (<anonymous>)