how to fix this?
working/278657427/c3runtime.js:5168:2: ERROR - [JSC_LANGUAGE_FEATURE] This language feature is only supported for UNSTABLE mode or better: Public class fields.
5168| to_degrees = function(x)
^
working/278657427/c3runtime.js:5173:2: ERROR - [JSC_LANGUAGE_FEATURE] This language feature is only supported for UNSTABLE mode or better: Public class fields.
5173| to_clamped_degrees = function (x)
^
2 error(s), 0 warning(s)