Seems package-lock.json has been (partially) removed, will fix
Fixed

Migration guide needs a rebase it seems

@kurkle @LeeLenaleee fyi

Chart.js(feat-side-effects-false)$ npx eslint karma.conf.cjs 

/Users/dangreen/github/Chart.js/karma.conf.cjs
  9:15  error  Multiple spaces found before '='       no-multi-spaces
  9:26  error  ES2020 'import()' syntax is forbidden  es/no-dynamic-import

✖ 2 problems (2 errors, 0 warnings)
  1 error and 0 warnings potentially fixable with the `--fix` option.

Interesting ci did not fail on it, will look at it later

@dangreen I don't seen the get the error when runnning npm run lint-js so I guess your way of running eslint might take another config file.

EDIT:
I don't know why why eslint does not lint the file because it should indeed flag the double space with the normal way of running it, guess it's fine for now since it does not trigger with the npm scripts , if it does we need to adjust the eslint config to either allow dynamic imports or disable linting of the karma configuration

@LeeLenaleee run directly npx eslint karma.conf.cjs