Uncaught TypeError: Failed to execute 'readAsDataURL' on 'FileReader': parameter 1 is not of type 'Blob'

Question

I\'ve got a problem with a javascript Filereader which returns the error Uncaught TypeError: Failed to execute \'readAsDataURL\' on \'FileReader\': parameter 1 is not of type \'

Answer 1

You need to make sure file has a value (not undefined or null).

At the top of imageFunction:

if(!file) {
    // handle error condition and return
}