async-await.js

async function fetchAsObjectURL(url) {
    const response = await fetch(url);
    const blob = await response.blob();
    return URL.createObjectURL(blob);
}

fetchAsObjectURL('https://jsonplaceholder.typicode.com/todos/1');

generator.js

function *fetchAsObjectURL(url) {
    const response = yield fetch(url);
    const blob = yield response.blob();
    return URL.createObjectURL(blob);
}

runAsync(fetchAsObjectURL('https://jsonplaceholder.typicode.com/todos/1'));