问题
when we use fetch
in JS to issue a get request, we normally do thing like this
fetch(endpoint).then(res => res.json()).then(result => ...)
However I was watching Wes Bos's JS 30 courses and he called the intermediate result that the fetch returns a blob
as in
fetch(endpoint).then(blob => blob.json()).then(result => ...)
I found the definition for blob here https://developer.mozilla.org/en-US/docs/Web/API/Blob
I am not knowledgable enough to judge if Wes Bos was using the right term here to refer to it as blob
and I have no ways to contact him directly and ask him. Hope I can find some answers here.
回答1:
fetch
returns a Response object, not a Blob - if you try to use blob methods like .slice
and .stream
on the result, errors will be thrown, since those methods do not exist.
// Not OK:
fetch('data:,Hello%2C%20World!').then(blob => blob.slice()).catch((err) => console.log('err', err.message));
// OK:
fetch('data:,Hello%2C%20World!').then(res => res.text()).then(console.log);
Note that the Response can be converted into a Blob, but the return value from fetch
would still be a Response:
fetch(endpoint)
.then(response => response.blob())
.then((blob) => {
// work with the blob here
});
Calling the response a blob is incorrect. They're somewhat similar, but not the same. Better to avoid calling it a blob
to avoid confusion.
来源:https://stackoverflow.com/questions/61035624/what-should-the-intermediate-result-that-a-fetch-request-returns-be-called-a-bl