How to upload / download all format excel file to azure blob storage Nodejs server side

I create a azure function and maybe you can use parse-multipart to receive your files:

Install:

npm install parse-multipart

Code:

import { AzureFunction, Context, HttpRequest } from "@azure/functions"
import { DefaultAzureCredential } from '@azure/identity';
import { BlobServiceClient } from '@azure/storage-blob';

const httpTrigger: AzureFunction = async function (context: Context, req: HttpRequest): Promise<void> {
    var multipart = require('parse-multipart');
    var bodyBuffer = Buffer.from(req.body);
    var boundary = multipart.getBoundary(req.headers['content-type']);
    var parts = multipart.Parse(bodyBuffer, boundary);

    // Enter your storage account name
    const account = process.env.ACCOUNT_NAME;

    // Unique name for the container
    const containerName = process.env.CONTAINER_NAME;

    // Azure AD Credential information is required to run this sample:
    if (
      !process.env.AZURE_TENANT_ID ||
      !process.env.AZURE_CLIENT_ID ||
      !process.env.AZURE_CLIENT_SECRET || !account || !containerName
    ) {
      return next(SystemResponse.badRequestError('Azure AD authentication information not provided, but it is required to run this sample. Exiting.'));
    }

    const defaultAzureCredential = new DefaultAzureCredential();
    const blobServiceClient = new BlobServiceClient(
      `https://${account}.blob.core.windows.net`,
      defaultAzureCredential,
    );



    // Get a reference to a container
    const containerClient = blobServiceClient.getContainerClient(containerName);

    // Upload data to the blob
    const blobName = `${parts[0].filename.split('.')[0]}+${new Date().getTime()}.${parts[0].filename.split('.')[1]}`;

    // create blobClient for container
    const blockBlobClient = containerClient.getBlockBlobClient(blobName);

    // upload file
    const uploadBlobResponse = await blockBlobClient.upload(parts[0].data , parts[0].data.length);
};

Reason:

function upload(body: HttpRequestBody, contentLength: number, options?: BlockBlobUploadOptions)

The value of the HttpRequestBody should be Blob, string, ArrayBuffer, ArrayBufferView or a function which returns a new Readable stream whose offset is from data source beginning, so you shouldn't use path.

================update=======================

According to the discussion, the file should be read according to the relative path, and the binary data of the file should be converted into a base64 string.

var fs = require('fs');
var path = require('path'); 
//set relative path to file 
let relativePath = path.relative(process.cwd(),${req.files.file.path}); 
//reading binary data of file 
let binaryData=fs.readFileSync(relativePath); 
//converting binary data to base64 string 
let base64String=Buffer.from(binaryData).toString("base64")
await blockBlobClient.upload(base64String, req.files.file.size);

================update2====================

    const containerClient = blobServiceClient.getContainerClient(containerName);

    // Upload data to the blob
    const blobName = `xxx.xlsx`;

    // create blobClient for container
    const blockBlobClient = containerClient.getBlockBlobClient(blobName);

    const downloadBlockBlobResponse = blockBlobClient.downloadToFile("D:\\xxx\\xxx.xlsx");