show pdf before upload

[Cooper1886]

hi, i meet some trouble,
i want to show the pdf before upload, so when i got the PDF file, i did like that
const reader = new FileReader(); reader.readAsDataURL(files.compare); reader.onload = (e) => { console.log(e.target.result, 'reader----------'); setDisplayPdf(e.target.result); };
but it doesnt work

at last, i hope somebody can help me, i'll be grateful.