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useDownloadBlob Hook

useDownloadBlob hook is used to directly download a file as bytes from Firebase Storage. Instead of useDownloadLink hook, this hook might be useful to process a file byte by byte instead of directly downloading to the user's machine.

A very simple example would be:

const reference = ref(storage, "path/to/remote/file.png");
const { dispatch } = useDownloadBlob(reference);
const blob = await dispatch(file);


useDownloadBlob is lazy by default and will not do anything until you use dispatch function.

You can get the state of the progress with this example.

const { state } = useDownloadBlob(reference);
const blob = await dispatch();
// `state` is "ready" | "loading" | "done"

dispatch method will return an instance of Blob, but additionally, you can also listen to Blob from useDownloadBlob hook as well:

const { blob } = useDownloadBlob(reference);
// blob updates and rerenders when the state is `"done"`
// until then, it is `undefined`
await dispatch();

Input Parameters

Input parameters for useDownloadBlob hook is as follows:

Name Type Description Required Default Value
reference firebase/storage/StorageReference Reference to a file in Storage. -

Return Type

useDownloadBlob hook returns an object with properties as below:

Name Type Description
blob Blob or undefined The blob of remote file to read. undefined if the state is not "done".
state "ready" | "loading" | "done" The state of the process.
dispatch (maxDownloadSizeBytes? number) => Promise<string> A callback to start the process and return the link. You can also define how many bytes to download at most.