TypeError at build on custom Yup method (with Next.js)

Describe the bug A type TypeError is thrown at build time (Next.js) due to custom Yup method.

To Reproduce Declare a custom Yup method

Yup.addMethod(Yup.mixed, 'fileSize', function (
    MAX_FILE_SIZE = DEFAULT_MAX_FILE_SIZE
  ) {
    return this.test(
      'fileSize',
      { key: 'common:validation.mixed.upload.file_size' },
      (value) => get(value, '[0].size', 0) <= MAX_FILE_SIZE
    );
  });

Try to use this method in Yup schema and build your application

Expected behavior My project is not using Typescript. No issue on development environment (next dev).

The application build should work normally.

Platform (please complete the following information):

"yup": "^0.29.3"
"next": "^9.5.5"

Additional context

[jquense]

not sure, seems like Next specific issue. The only reason it would undefined is if the addMethod code didn’t run

[clement-faure]

Why this is issue is closed? @clement-faure Have you found a way to fix this issue?

I din’t manage to make it work using a custom yup method so i ended up creating my own yup configuration file and exporting

export const YupFile = ({
  fileSize = DEFAULT_MAX_FILE_SIZE,
  fileTypes = DEFAULT_SUPPORTED_FORMATS,
} = {}) =>
  Yup.mixed()
    .test(
      'fileSize',
      { key: 'common:validation.mixed.upload.file_size' },
      (value) => {
        if (isArray(value)) {
          // In case array of files, check every file
          return value
            .map((file) => isValidFileSize(file, fileSize)) // (file, fileSize) => get(file, 'size', 0) <= fileSize
            .reduce((a, b) => a && b);
        }
        // Otherwise, only one single file
        return isValidFileSize(file, fileSize);
      }
    )
    .test(
      'fileType',
      { key: 'common:validation.mixed.upload.file_type' },
      (value) => {
        if (isArray(value)) {
          return value
            .map((file) => isValidFileType(file, fileTypes)) // (file, fileTypes) => fileTypes.includes(get(file, 'type', 'image/png')
            .reduce((a, b) => a && b);
        }
        return isValidFileType(file, fileTypes);
      }
    );