Azion Unenv Preset

A preset configuration for unenv that provides polyfills and environment compatibility for Azion Edge Runtime.

Table of Contents

• Installation
• Usage
• Features
  • Node.js Polyfills
  • File System Polyfills
• API Reference
  • getFileContent
  • closeSync
  • openSync
  • statSync
  • readFileSync
  • readdirSync
• Contributing

Installation

Install the package using npm or yarn:

npm install azion

or

yarn add azion

Usage

The preset can be used with unenv to provide compatibility between Node.js and Azion Edge Runtime environments:

import { preset } from '@aziontech/unenv-preset';
// Use with unenv
export default {
  preset: preset,
};

Features

Node.js Polyfills

This preset provides polyfills for common Node.js APIs to ensure compatibility when running code in the Azion Edge Runtime environment. The following modules are polyfilled:

• crypto - Complete cryptographic functionality including hashing, encryption, and UUID generation
• events - Event handling through events/events.js
• http - HTTP client functionality via stream-http
• module - Basic module system compatibility (limited functionality)
• stream - Stream implementations via stream-browserify
• string_decoder - String decoding utilities
• url - URL parsing and formatting
• util - Utility functions
• timers - Timer functions via timers-browserify
• vm - Virtual Machine functionality via vm-browserify
• zlib - Compression functionality via browserify-zlib

Example using crypto polyfill:

import { createHash, randomUUID } from '@aziontech/unenv-preset/polyfills/node/crypto';

// Create a hash
const hash = createHash('sha256');
hash.update('some data');
console.log(hash.digest('hex'));

// Generate a UUID
const uuid = randomUUID();

File System Polyfills

The preset includes comprehensive file system polyfills that mirror Node.js's fs module functionality. These polyfills work with an in-memory file system when running in the Edge Runtime.

Basic File Operations

import { readFileSync, writeFileSync } from '@aziontech/unenv-preset/polyfills/node/fs';

// Read a file
const content = readFileSync('/path/to/file.txt', 'utf8');

// Write to a file
writeFileSync('/path/to/new-file.txt', 'Hello World', 'utf8');

Directory Operations

import { readdirSync, mkdirSync } from '@aziontech/unenv-preset/polyfills/node/fs';

// List directory contents
const files = readdirSync('/path/to/dir');

// Create a directory
mkdirSync('/path/to/new-dir');

File Stats and Information

import { statSync, existsSync } from '@aziontech/unenv-preset/polyfills/node/fs';

// Check if file exists
if (existsSync('/path/to/file.txt')) {
  // Get file stats
  const stats = statSync('/path/to/file.txt');
  console.log(`File size: ${stats.size}`);
  console.log(`Is directory: ${stats.isDirectory()}`);
  console.log(`Is file: ${stats.isFile()}`);
}

File Descriptors

import { openSync, closeSync, readSync } from '@aziontech/unenv-preset/polyfills/node/fs';

// Open file and get file descriptor
const fd = openSync('/path/to/file.txt', 'r');

// Read from file descriptor
const buffer = Buffer.alloc(1024);
readSync(fd, buffer, 0, 1024, 0);

// Close file descriptor
closeSync(fd);

Global Polyfills

The preset also provides polyfills for Node.js global variables and objects:

• __dirname - Current directory name
• __filename - Current file name
• process - Process information and environment (including env variables)
• performance - Performance timing functionality
• navigator - Browser-compatible navigator object

The preset also handles injection of these globals through the unenv configuration:

import { preset } from '@aziontech/unenv-preset';

// Preset configuration automatically injects globals
export default {
  inject: {
    __dirname: preset.inject.__dirname,
    __filename: preset.inject.__filename,
    process: preset.inject.process,
    performance: preset.inject.performance,
    navigator: preset.inject.navigator,
  },
};

API Reference

getFileContent

Decodes file content and returns it as either a Buffer or string.

Parameters:

• file - The file object containing content in base64 format
• returnBuffer - (Optional) Boolean to determine return type (default: true)
  • true returns Buffer
  • false returns string

Returns:

• Buffer | string - The decoded file content

Example:

const fileBuffer = getFileContent(file); // returns Buffer
const fileString = getFileContent(file, false); // returns string

closeSync

Synchronously closes the file descriptor.

Parameters:

• fd - The file descriptor to close.

Example:

closeSync(fd);

openSync

Synchronously opens a file.

Parameters:

• path - The path to the file.
• flags - The opening mode (e.g., 'r', 'w').
• mode - (Optional) The file mode.

Returns:

• number - The file descriptor.

Example:

const fd = openSync('/path/to/file.txt', 'r');

statSync

Synchronously retrieves the fs.Stats for the specified path.

Parameters:

• path - The path to the file or directory.
• options - (Optional) Options for the stat call.

Returns:

• fs.Stats - The stats object for the file or directory.

Example:

const stats = statSync('/path/to/file.txt');

readFileSync

Synchronously reads the entire contents of a file.

Parameters:

• path - The path to the file.
• options - (Optional) Options for reading the file.

Returns:

• string | Buffer - The contents of the file.

Example:

const content = readFileSync('/path/to/file.txt', 'utf8');

readdirSync

Synchronously reads the contents of a directory.

Parameters:

• path - The path to the directory.
• options - (Optional) Options for reading the directory.

Returns:

• string[] - An array of file names in the directory.

Example:

const files = readdirSync('/path/to/dir');

Contributing

Contributions are welcome! Please read our contributing guidelines for details on our code of conduct and the process for submitting pull requests.