appwrite/app/sdks/javascript/docs/examples/storage/get-file-download.md

let sdk = new Appwrite();

sdk
    .setProject('5df5acd0d48c2') // Your project ID
;

let promise = sdk.storage.getFileDownload('[FILE_ID]');

promise.then(function (response) {
    console.log(response);
}, function (error) {
    console.log(error);
});