SOURCE

var domString = ['<p>123</p>'];
var blob = new Blob(domString, { type: 'text/html' });

var reader = new FileReader();
reader.onload = (e) => {
    console.log('FileReader read blob', e.target.result);
};
// reader.readAsArrayBuffer(blob);
reader.readAsText(blob, 'utf-8');

console.log('blob', blob);
console.log('blob.text', blob.text());
console.log('blob.stream', blob.stream());
console.log('blob.arrayBuffer', blob.arrayBuffer());
blob.slice(3, 6).text().then(t => {
    console.log('blob.slice', t);
})