@azure/storage-blob (TypeScript/JavaScript)

@azure/​storage-blob (TypeScript/​JavaScript)

SDK for Azure Blob Storage operations — upload, download, list, and manage blobs and containers.

Installation

npm install @azure/​storage-blob @azure/​identity

Current Version: 12.x
Node.js: >= 18.0.0

Environment Variables

AZURE_STORAGE_ACCOUNT_NAME=<account-name>
AZURE_STORAGE_ACCOUNT_KEY=<account-key>
# OR connection string
AZURE_STORAGE_CONNECTION_STRING=DefaultEndpointsProtocol=https;AccountName=...

Authentication

DefaultAzureCredential (Recommended)

import { BlobServiceClient } from "@azure/​storage-blob";
import { DefaultAzureCredential } from "@azure/​identity";

const accountName = process.env.AZURE_STORAGE_ACCOUNT_NAME!;
const client = new BlobServiceClient(
  `https://${accountName}.blob.core.windows.net`,
  new DefaultAzureCredential()
);

Connection String

import { BlobServiceClient } from "@azure/​storage-blob";

const client = BlobServiceClient.fromConnectionString(
  process.env.AZURE_STORAGE_CONNECTION_STRING!
);

StorageSharedKeyCredential (Node.js only)

import { BlobServiceClient, StorageSharedKeyCredential } from "@azure/​storage-blob";

const accountName = process.env.AZURE_STORAGE_ACCOUNT_NAME!;
const accountKey = process.env.AZURE_STORAGE_ACCOUNT_KEY!;

const sharedKeyCredential = new StorageSharedKeyCredential(accountName, accountKey);
const client = new BlobServiceClient(
  `https://${accountName}.blob.core.windows.net`,
  sharedKeyCredential
);

SAS Token

import { BlobServiceClient } from "@azure/​storage-blob";

const accountName = process.env.AZURE_STORAGE_ACCOUNT_NAME!;
const sasToken = process.env.AZURE_STORAGE_SAS_TOKEN!; // starts with "?"

const client = new BlobServiceClient(
  `https://${accountName}.blob.core.windows.net${sasToken}`
);

Client Hierarchy

BlobServiceClient (account level)
└── ContainerClient (container level)
    └── BlobClient (blob level)
        ├── BlockBlobClient (block blobs - most common)
        ├── AppendBlobClient (append-only blobs)
        └── PageBlobClient (page blobs - VHDs)

Container Operations

Create Container

const containerClient = client.getContainerClient("my-container");
await containerClient.create();

// Or create if not exists
await containerClient.createIfNotExists();

List Containers

for await (const container of client.listContainers()) {
  console.log(container.name);
}

// With prefix filter
for await (const container of client.listContainers({ prefix: "logs-" })) {
  console.log(container.name);
}

Delete Container

await containerClient.delete();
// Or delete if exists
await containerClient.deleteIfExists();

Blob Operations

Upload Blob (Simple)

const containerClient = client.getContainerClient("my-container");
const blockBlobClient = containerClient.getBlockBlobClient("my-file.txt");

// Upload string
await blockBlobClient.upload("Hello, World!", 13);

// Upload Buffer
const buffer = Buffer.from("Hello, World!");
await blockBlobClient.upload(buffer, buffer.length);

Upload from File (Node.js only)

const blockBlobClient = containerClient.getBlockBlobClient("uploaded-file.txt");
await blockBlobClient.uploadFile("/​path/​to/​local/​file.txt");

Upload from Stream (Node.js only)

import * as fs from "fs";

const blockBlobClient = containerClient.getBlockBlobClient("streamed-file.txt");
const readStream = fs.createReadStream("/​path/​to/​local/​file.txt");

await blockBlobClient.uploadStream(readStream, 4 * 1024 * 1024, 5, {
  // bufferSize: 4MB, maxConcurrency: 5
  onProgress: (progress) => console.log(`Uploaded ${progress.loadedBytes} bytes`),
});

Upload from Browser

const blockBlobClient = containerClient.getBlockBlobClient("browser-upload.txt");

// From File input
const fileInput = document.getElementById("fileInput") as HTMLInputElement;
const file = fileInput.files![0];
await blockBlobClient.uploadData(file);

// From Blob/​ArrayBuffer
const arrayBuffer = new ArrayBuffer(1024);
await blockBlobClient.uploadData(arrayBuffer);

Download Blob

const blobClient = containerClient.getBlobClient("my-file.txt");
const downloadResponse = await blobClient.download();

// Read as string (browser & Node.js)
const downloaded = await streamToText(downloadResponse.readableStreamBody!);

async function streamToText(readable: NodeJS.ReadableStream): Promise<string> {
  const chunks: Buffer[] = [];
  for await (const chunk of readable) {
    chunks.push(Buffer.from(chunk));
  }
  return Buffer.concat(chunks).toString("utf-8");
}

Download to File (Node.js only)

const blockBlobClient = containerClient.getBlockBlobClient("my-file.txt");
await blockBlobClient.downloadToFile("/​path/​to/​local/​destination.txt");

Download to Buffer (Node.js only)