dayjs.extend() and dayjs.locale() result in an error when dayjs is imported from ESM bundle

Describe the bug

Extending with plugins and setting locale doesn’t seem to work when using ESM bundle. Following code produces following errors when used in Angular Typescript project.

import * as dayjs from 'dayjs/esm';
import 'dayjs/esm/locale/en-gb';
import * as customParseFormat from 'dayjs/esm/plugin/customParseFormat';

dayjs.locale('en-gb');
dayjs.extend(customParseFormat);

"export 'extend' (imported as 'dayjs') was not found in 'dayjs/esm'
"export 'locale' (imported as 'dayjs') was not found in 'dayjs/esm'

The code above works fine when importing directly from dayjs instead of dayjs/esm.

Information

• Day.js Version 1.9.6
• Angular v10

[shayke]

Now in 1.10.0 due to https://github.com/iamkun/dayjs/issues/313 These imports don’t work anymore since ESM is used by default:

import * as dayjs from 'dayjs/esm';
import 'dayjs/esm/locale/en-gb';
import * as customParseFormat from 'dayjs/esm/plugin/customParseFormat';

For now i’ve added an alias in my webpack config if anyone is interested as a workaround: 'dayjs$': path.resolve(path.join(__dirname, 'node_modules/dayjs/dayjs.min.js')),

[iamkun]

Seems a nice choice. We’ll think about that.