fetch

So, the fetch API is landing in Safari. I'm surprised, since the Safari implementation presumably still lacks the ability to abort a request as it does in Chrome. Since the discussion on how to resolve this issue is ongoing[1], I thought they'd wait until a decision was reached. Must be gearing up for Service Workers & Web Push — something I expected to be at the bottom of the priority list for Apple's browser. [1] https://github.com/whatwg/fetch/issues/27

This thread has a much more in-depth discussion on the considerations for designing this API: https://github.com/whatwg/fetch/issues/27 One key point is: since a promise can have multiple then-subscribers interested in it, (a) is it the subscriber's responsibility to signal disinterest (in which case the promise-creator needs to reference-count interest/disinterest)? Or (b) is it the promise-creator's responsibility to unilaterally cancel things, and the entire dependency tree must figure out how to fail elegantly? Either way, in a cancellation world, subscribers need to be rewritten either to (a) indicate disinterest, or (b) handle a cancellation coming from upstream, which is semantically distinct from an error. Bluebird (whose designers seem to be involved in that thread) handles (a) pretty elegantly - it's subtle, but cancelablePromis

In fetch's defence it will in future once the Streams API is finalised: https://github.com/whatwg/fetch/issues/21

I find fetch very painful to use since the promises don't reject on non-2XX! I use axios instead. This is especially so sad when using async/await :( https://github.com/whatwg/fetch/issues/18 fetch(url) .then((res) => { if (res.statusCode < 200 || res.statusCode > 299) { throw new Error("Why do I have to write this with every request?"); } });