Same you don’t have different checks to grab fetch, because it’s not cross platform. You don’t have 3 different checks … nobody does. And if you're looking for a polyfill, check out GitHub's implementation. For a more in depth look, please visit Introduction to Fetch. This is meant to be an introduction to fetch. I can't wait until fetch is more broadly supported! After all, it was created so that we could do AJAX the right way fetch has the advantage of hindsight. The new fetch API seems much saner and simpler to use than XHR. While fetch is a nicer API to use, the API current doesn't allow for canceling a request, which makes it a non-starter for many developers. Very easy, very eye-pleasing as well! Unwritten Story Posting Form DataĪnother common use case for AJAX is sending form data - here's how you would use fetch to post form data:īody: new FormData(document.getElementById('comment-form'))Īnd if you want to POST JSON to the server:Įmail: document.getElementById('email').value,Īnswer: document.getElementById('answer').value The blob() method of the Body mixin takes a Response stream and reads it to completion. If you want to load an image via fetch, for example, that will be a bit different:ĭocument.querySelector('img').src = URL.createObjectURL(imageBlob) You can get the response text via chaining the Promise's then method along with the text() method. JSON isn't always the desired request response format so here's how you can work with an HTML or text response: Of course that's a simple JSON.parse(jsonString), but the json method is a handy shortcut. Let's say you make a request for JSON - the resulting callback data has a json method for converting the raw data to a JavaScript object: text() - Returns a promise that resolves with a USVString (text).json() - Returns a promise that resolves with a JSON object.formData() - Returns a promise that resolves with a FormData object.blob() - Returns a promise that resolves with a Blob.
arrayBuffer() - Returns a promise that resolves with an ArrayBuffer.redirect() - Creates a new response with a different URL.error() - Returns a new Response object associated with a network error.clone() - Creates a clone of a Response object.The Response also provides the following methods: The fetch's `then` gets a Response instance backĬonsole.log('status: ', responseObj.status) Create your own response for service worker testing headers - Headers object associated with the response.ok - Boolean for successful response (status in the range 200-299).useFinalURL - Boolean for if url is the final URL.The fetch's then method is provided a Response instance but you can also manually create Response objects yourself - another situation you may encounter when using service workers. You'll likely only use Request instances within Service Workers since the Request and fetch signatures can be the same. XHR is a bit overcomplicated in my opinion, and don't get me started on why "XML" is uppercase but "Http" is camel-cased. Let's have a basic look at the new window.fetch method, available now in Firefox and Chrome Canary. Our effort to do better is the fetch API. We've done well to create elegant APIs around XHR but we know we can do better. One of the worst kept secrets about AJAX on the web is that the underlying API for it, XMLHttpRequest, wasn't really made for what we've been using it for.
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