Convert arrayBuffer to base64 string
arrayBufferToBase64(Arraybuffer, Filetype, fileName) {
let binary = '';
const bytes = new Uint8Array(Arraybuffer);
const len = bytes.byteLength;
for (let i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i]);
}
const file = window.btoa(binary);
const mimType = Filetype === 'pdf' ? 'application/pdf' : Filetype === 'xlsx' ? 'application/xlsx' :
Filetype === 'pptx' ? 'application/pptx' : Filetype === 'csv' ? 'application/csv' : Filetype === 'docx' ? 'application/docx' :
Filetype === 'jpg' ? 'application/jpg' : Filetype === 'png' ? 'application/png' : '';
const url = `data:${mimType};base64,` + file;
// url for the file
this.fileUrl = this.sanitizer.bypassSecurityTrustResourceUrl(url);
// download the file
const a = document.createElement('a');
a.href = url;
a.download = fileName;
document.body.appendChild(a);
a.click();
document.body.removeChild(a);
window.URL.revokeObjectURL(url);
}