@azure/storage-file-share (TypeScript/JavaScript)

SDK for Azure File Share operations — SMB file shares, directories, and file operations.

Installation

npm install @azure/storage-file-share @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=...
AZURE_TOKEN_CREDENTIALS=prod # Required only if DefaultAzureCredential is used in production

Authentication

Connection String (Simplest)

import { ShareServiceClient } from "@azure/storage-file-share";

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

StorageSharedKeyCredential (Node.js only)

import { ShareServiceClient, StorageSharedKeyCredential } from "@azure/storage-file-share";

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 ShareServiceClient(
  `https://${accountName}.file.core.windows.net`,
  sharedKeyCredential
);

Microsoft Entra Token Credential

import { ShareServiceClient } from "@azure/storage-file-share";
import { DefaultAzureCredential, ManagedIdentityCredential } from "@azure/identity";

// Local dev: DefaultAzureCredential. Production: set AZURE_TOKEN_CREDENTIALS=prod or AZURE_TOKEN_CREDENTIALS=<specific_credential>
const credential = new DefaultAzureCredential({requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"]});
// Or use a specific credential directly in production:
// See https://learn.microsoft.com/javascript/api/overview/azure/identity-readme?view=azure-node-latest#credential-classes
// const credential = new ManagedIdentityCredential();

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

SAS Token

import { ShareServiceClient } from "@azure/storage-file-share";

const accountName = process.env.AZURE_STORAGE_ACCOUNT_NAME!;
const sasToken = process.env.AZURE_STORAGE_SAS_TOKEN!;

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

Client Hierarchy

ShareServiceClient (account level)
└── ShareClient (share level)
    └── ShareDirectoryClient (directory level)
        └── ShareFileClient (file level)

Share Operations

Create Share

const shareClient = client.getShareClient("my-share");
await shareClient.create();

// Create with quota (in GB)
await shareClient.create({ quota: 100 });

List Shares

for await (const share of client.listShares()) {
  console.log(share.name, share.properties.quota);
}

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

Delete Share

await shareClient.delete();

// Delete if exists
await shareClient.deleteIfExists();

Get Share Properties

const properties = await shareClient.getProperties();
console.log("Quota:", properties.quota, "GB");
console.log("Last Modified:", properties.lastModified);

Set Share Quota

await shareClient.setQuota(200); // 200 GB

Directory Operations

Create Directory

const directoryClient = shareClient.getDirectoryClient("my-directory");
await directoryClient.create();

// Create nested directory
const nestedDir = shareClient.getDirectoryClient("parent/child/grandchild");
await nestedDir.create();

List Directories and Files

const directoryClient = shareClient.getDirectoryClient("my-directory");

for await (const item of directoryClient.listFilesAndDirectories()) {
  if (item.kind === "directory") {
    console.log(`[DIR] ${item.name}`);
  } else {
    console.log(`[FILE] ${item.name} (${item.properties.contentLength} bytes)`);
  }
}

Delete Directory

await directoryClient.delete();

// Delete if exists
await directoryClient.deleteIfExists();

Check if Directory Exists

const exists = await directoryClient.exists();
if (!exists) {
  await directoryClient.create();
}

File Operations

Upload File (Simple)

const fileClient = shareClient
  .getDirectoryClient("my-directory")
  .getFileClient("my-file.txt");

// Upload string
const content = "Hello, World!";
await fileClient.create(content.length);
await fileClient.uploadRange(content, 0, content.length);

Upload File (Node.js - from local file)

import * as fs from "fs";
import * as path from "path";

const fileClient = shareClient.rootDirectoryClient.getFileClient("uploaded.txt");
const localFilePath = "/path/to/local/file.txt";
const fileSize = fs.statSync(localFilePath).size;

await fileClient.create(fileSize);
await fileClient.uploadFile(localFilePath);

Upload File (Buffer)

const buffer = Buffer.from("Hello, Azure Files!");
const fileClient = shareClient.rootDirectoryClient.getFileClient("buffer-file.txt");

await fileClient.create(buffer.length);
await fileClient.uploadRange(buffer, 0, buffer.length);

Upload File (Stream)

import * as fs from "fs";

const fileClient = shareClient.rootDirectoryClient.getFileClient("streamed.txt");
const readStream = fs.createReadStream("/path/to/local/file.txt");
const fileSize = fs.statSync("/path/to/local/file.txt").size;

await fileClient.create(fileSize);
await fileClient.uploadStream(readStream, fileSize, 4 * 1024 * 1024, 4); // 4MB buffer, 4 concurrency

Download File

const fileClient = shareClient
  .getDirectoryClient("my-directory")
  .getFileClient("my-file.txt");

const downloadResponse = await fileClient.download();

// Read as string
const chunks: Buffer[] = [];
for await (const chunk of downloadResponse.readableStreamBody!) {
  chunks.push(Buffer.from(chunk));
}
const content = Buffer.concat(chunks).toString("utf-8");

Download to File (Node.js)

const fileClient = shareClient.rootDirectoryClient.getFileClient("my-file.txt");
await fileClient.downloadToFile("/path/to/local/destination.txt");

Download to Buffer (Node.js)

const fileClient = shareClient.rootDirectoryClient.getFileClient("my-file.txt");
const buffer = await fileClient.downloadToBuffer();
console.log(buffer.toString());

Delete File

const fileClient = shareClient.rootDirectoryClient.getFileClient("my-file.txt");
await fileClient.delete();

// Delete if exists
await fileClient.deleteIfExists();

Copy File

const sourceUrl = "https://account.file.core.windows.net/share/source.txt";
const destFileClient = shareClient.rootDirectoryClient.getFileClient("destination.txt");

// Start copy operation
const copyPoller = await destFileClient.startCopyFromURL(sourceUrl);
await copyPoller.pollUntilDone();

File Properties & Metadata

Get File Properties

const fileClient = shareClient.rootDirectoryClient.getFileClient("my-file.txt");
const properties = await fileClient.getProperties();

console.log("Content-Length:", properties.contentLength);
console.log("Content-Type:", properties.contentType);
console.log("Last Modified:", properties.lastModified);
console.log("ETag:", properties.etag);

Set Metadata

await fileClient.setMetadata({
  author: "John Doe",
  category: "documents",
});

Set HTTP Headers

await fileClient.setHttpHeaders({
  fileContentType: "text/plain",
  fileCacheControl: "max-age=3600",
  fileContentDisposition: "attachment; filename=download.txt",
});

Range Operations

Upload Range

const data = Buffer.from("partial content");
await fileClient.uploadRange(data, 100, data.length); // Write at offset 100

Download Range

const downloadResponse = await fileClient.download(100, 50); // offset 100, length 50

Clear Range

await fileClient.clearRange(0, 100); // Clear first 100 bytes

Snapshot Operations

Create Snapshot

const snapshotResponse = await shareClient.createSnapshot();
console.log("Snapshot:", snapshotResponse.snapshot);

Access Snapshot

const snapshotShareClient = shareClient.withSnapshot(snapshotResponse.snapshot!);
const snapshotFileClient = snapshotShareClient.rootDirectoryClient.getFileClient("file.txt");
const content = await snapshotFileClient.downloadToBuffer();

Delete Snapshot

await shareClient.delete({ deleteSnapshots: "include" });

SAS Token Generation (Node.js only)

Generate File SAS

import {
  generateFileSASQueryParameters,
  FileSASPermissions,
  StorageSharedKeyCredential,
} from "@azure/storage-file-share";

const sharedKeyCredential = new StorageSharedKeyCredential(accountName, accountKey);

const sasToken = generateFileSASQueryParameters(
  {
    shareName: "my-share",
    filePath: "my-directory/my-file.txt",
    permissions: FileSASPermissions.parse("r"), // read only
    expiresOn: new Date(Date.now() + 3600 * 1000), // 1 hour
  },
  sharedKeyCredential
).toString();

const sasUrl = `https://${accountName}.file.core.windows.net/my-share/my-directory/my-file.txt?${sasToken}`;

Generate Share SAS

import { ShareSASPermissions, generateFileSASQueryParameters } from "@azure/storage-file-share";

const sasToken = generateFileSASQueryParameters(
  {
    shareName: "my-share",
    permissions: ShareSASPermissions.parse("rcwdl"), // read, create, write, delete, list
    expiresOn: new Date(Date.now() + 24 * 3600 * 1000), // 24 hours
  },
  sharedKeyCredential
).toString();

Error Handling

import { RestError } from "@azure/storage-file-share";

try {
  await shareClient.create();
} catch (error) {
  if (error instanceof RestError) {
    switch (error.statusCode) {
      case 404:
        console.log("Share not found");
        break;
      case 409:
        console.log("Share already exists");
        break;
      case 403:
        console.log("Access denied");
        break;
      default:
        console.error(`Storage error ${error.statusCode}: ${error.message}`);
    }
  }
  throw error;
}

TypeScript Types Reference

import {
  // Clients
  ShareServiceClient,
  ShareClient,
  ShareDirectoryClient,
  ShareFileClient,

  // Authentication
  StorageSharedKeyCredential,
  AnonymousCredential,

  // SAS
  FileSASPermissions,
  ShareSASPermissions,
  AccountSASPermissions,
  AccountSASServices,
  AccountSASResourceTypes,
  generateFileSASQueryParameters,
  generateAccountSASQueryParameters,

  // Options & Responses
  ShareCreateResponse,
  FileDownloadResponseModel,
  DirectoryItem,
  FileItem,
  ShareProperties,
  FileProperties,

  // Errors
  RestError,
} from "@azure/storage-file-share";

Best Practices

1. Use connection strings for simplicity — Easiest setup for development
2. Use DefaultAzureCredential for local development; use ManagedIdentityCredential or WorkloadIdentityCredential for production
3. Set quotas on shares — Prevent unexpected storage costs
4. Use streaming for large files — uploadStream/downloadToFile for files > 256MB
5. Use ranges for partial updates — More efficient than full file replacement
6. Create snapshots before major changes — Point-in-time recovery
7. Handle errors gracefully — Check RestError.statusCode for specific handling
8. Use *IfExists methods — For idempotent operations

Platform Differences

Feature	Node.js	Browser
StorageSharedKeyCredential	✅	❌
uploadFile()	✅	❌
uploadStream()	✅	❌
downloadToFile()	✅	❌
downloadToBuffer()	✅	❌
SAS generation	✅	❌
DefaultAzureCredential	✅	❌
Anonymous/SAS access	✅	✅