blob-constructor.js

const data = {
  name: 'Glad Chinda',
  country: 'Nigeria',
  role: 'Web Developer'
};

// SOURCE 1:
// Creating a blob object from non-blob data using the Blob constructor
const blob = new Blob([ JSON.stringify(data) ], { type: 'application/json' });

blob-slice.js

const paragraphs = [
  'First paragraph.\r\n',
  'Second paragraph.\r\n',
  'Third paragraph.'
];
const blob = new Blob(paragraphs, { type: 'text/plain' });

// SOURCE 2:
// Creating a new blob by slicing part of an already existing blob object
const slicedBlob = blob.slice(0, 100);

fetch-blob.js

// SOURCE 3:
// Generating a blob object from a Web API like the Fetch API
// Notice that Response.blob() returns a promise that is fulfilled with a blob object
fetch('https://picsum.photos/id/6/100')
  .then(response => response.blob())
  .then(blob => {
    // use blob here...
  });