The built-in TextDecoder does exactly that. To create a string, we need to interpret these bytes. set(chunk, position) method to copy each chunk one after another in it. We create chunksAll = new Uint8Array(receivedLength) – a same-typed array with the combined length.
#Download fetch js code#
Unfortunately, there’s no single method that concatenates those, so there’s some code to do that: We need to join them into a single result. That’s important, because after the response is consumed, we won’t be able to “re-read” it using response.json() or another way (you can try, there’ll be an error).Īt the end, we have chunks – an array of Uint8Array byte chunks. We gather response chunks in the array chunks. But usually it’s at place.Ĭall await reader.read() until it’s done. It may be absent for cross-origin requests (see chapter Fetch: Cross-Origin Requests) and, well, technically a server doesn’t have to set it.
#Download fetch js full#
Prior to reading, we can figure out the full response length from the Content-Length header. In essence the Fetch API fetch () method returns a response, from which a blob can be. For the XHR request we use the Fetch API with the whatwg-fetch polyfill.
#Download fetch js pdf#
Please note, we can’t use both these methods to read the same response: either use a reader or a response method to get the result. To solve this it was necessary to download the file to memory with an XHR request and then get the browser to open or download it with whatever plugin/UI it normally uses for pdf file. We perform fetch as usual, but instead of calling response.json(), we obtain a stream reader (). Let result = new TextDecoder("utf-8").decode(chunksAll) Let chunksAll = new Uint8Array(receivedLength) // (4.1) Step 4: concatenate chunks into single Uint8Array Let chunks = // array of received binary chunks (comprises the body)Ĭonst `) Let receivedLength = 0 // received that many bytes at the moment Let queryParam = buildQueryParams(form.// Step 1: start the fetch and obtain a readerĬonst reader = () Ĭonst contentLength = +('Content-Length') When FileDownload is rendered and the form is submitted with method="GET" (POST should work too) and action= from "react".Since there is now a downloadPath, Widget will render FileDownload passing in the necessary props including downloadPath as well as the handleDownloadComplete method as the value for onDownloadComplete.The store saves the downloadPath and emits a change event. It dispatches a DOWNLOAD_FILE event to the store sending along with it the downloadPath for the file to download. The downloadFile action does NOT make an Ajax request.
All this component does is render a hidden form and then, inside componentDidMount, immediately submit the form and call it's onDownloadComplete prop.
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