A string or File that represents a single value from a set of FormData key-value pairs.

This type is returned by the FormData.get() and FormData.getAll() methods. The FormData.get() method returns a single value while FormData.getAll() returns an array of FormDataEntryValues.

Note that the FormData.append() and FormData.set() methods allow passing a Blob value, which is converted to a File in the process.