Multer Utility

A comprehensive TypeScript wrapper for Multer with enhanced features including memory/disk storage, flexible configuration, and file management utilities.

Features

- 🚀 TypeScript Support - Fully typed with comprehensive interfaces
- 💾 Multiple Storage Options - Memory and disk storage with easy switching
- 🔧 Flexible Configuration - Customizable file validation, naming, and storage options
- 🛡️ Advanced Validation - MIME type and extension validation with custom rules
- 📁 File Management - Built-in utilities for file operations and statistics
- 🎯 Specialized Uploaders - Pre-configured uploaders for images, audio, etc.
- 🔄 Memory & Disk Storage - Switch between storage types effortlessly

Installation

``bash
npm install multer-utility
`

Quick Start

$3

`typescript
import { UploadService } from 'multer-utility';
import express from 'express';

const app = express();
const uploader = new UploadService();

// Single file upload
app.post('/upload', uploader.single('file'), (req, res) => {
if (req.file) {
const fileInfo = uploader.getFileInfo(req.file);
res.json({ success: true, file: fileInfo });
}
});
`

$3

`typescript
import { createMemoryUploader } from 'multer-utility';

const memoryUploader = createMemoryUploader({
maxFileSize: 1024 1024 10, // 10MB
allowedMimeTypes: ['image/jpeg', 'image/png']
});

app.post('/upload-memory', memoryUploader.single('image'), (req, res) => {
if (req.file) {
// File is stored in memory as buffer
const buffer = req.file.buffer;
// Process the buffer as needed
res.json({ success: true, size: buffer.length });
}
});
`

$3

`typescript
import { createDiskUploader } from 'multer-utility';

const diskUploader = createDiskUploader('/custom/upload/path', {
maxFileSize: 1024 1024 50, // 50MB
useTimestamp: true,
sanitizeFilenames: true
});
`

Configuration Options

`typescript
interface UploadConfig {
// Storage configuration
storage?: 'disk' | 'memory';
uploadDir?: string;

// File validation
allowedMimeTypes?: string[];
allowedExtensions?: string[];
maxFileSize?: number; // in bytes

// Naming configuration
useTimestamp?: boolean;
sanitizeFilenames?: boolean;
customNaming?: (file: Express.Multer.File) => string;

// Advanced options
createDirIfNotExists?: boolean;
preserveOriginalName?: boolean;
}
`

Advanced Usage

$3

`typescript
const uploader = new UploadService({
storage: 'disk',
uploadDir: './uploads/documents',
allowedMimeTypes: ['application/pdf', 'image/jpeg', 'image/png'],
allowedExtensions: ['.pdf', '.jpg', '.jpeg', '.png'],
maxFileSize: 1024 1024 25, // 25MB
useTimestamp: true,
sanitizeFilenames: true,
customNaming: (file) => custom-${Date.now()}-${file.originalname}
});
`

$3

`typescript
// Array of files with same field name
app.post('/upload-multiple', uploader.array('files', 5), (req, res) => {
if (req.files && Array.isArray(req.files)) {
const fileInfos = req.files.map(file => uploader.getFileInfo(file));
res.json({ success: true, files: fileInfos });
}
});

// Multiple fields
app.post('/upload-fields', uploader.fields([
{ name: 'avatar', maxCount: 1 },
{ name: 'gallery', maxCount: 8 }
]), (req, res) => {
const files = req.files as { [fieldname: string]: Express.Multer.File[] };
res.json({ success: true, files });
});
`

$3

`typescript
import { createImageUploader, createAudioUploader } from 'multer-utility';

// Image uploader (JPEG, PNG, GIF, WebP)
const imageUploader = createImageUploader('./uploads/images');

// Audio uploader (MP3, WAV, OGG)
const audioUploader = createAudioUploader('./uploads/audio');

app.post('/upload-image', imageUploader.single('image'), (req, res) => {
// Handle image upload
});

app.post('/upload-audio', audioUploader.single('audio'), (req, res) => {
// Handle audio upload
});
`

File Management

$3

`typescript
const uploader = new UploadService({ storage: 'disk' });

// Check if file exists
const exists = uploader.fileExists('filename.jpg');

// Get file path
const filePath = uploader.getFilePath('filename.jpg');

// Delete file
const deleted = await uploader.deleteFile('filename.jpg');

// Get upload statistics
const stats = await uploader.getUploadStats();
console.log(stats);
// Output:
// {
// totalFiles: 15,
// totalSize: 2048576,
// files: [
// {
// name: 'file1.jpg',
// size: 102400,
// created: '2023-01-01T00:00:00.000Z',
// modified: '2023-01-01T00:00:00.000Z'
// }
// ]
// }
`

$3

`typescript
const uploader = new UploadService();

// Validate file manually
const validation = uploader.validateFile(file);
if (!validation.isValid) {
console.error(validation.error);
}
`

Error Handling

`typescript
app.post('/upload', uploader.single('file'), (req, res) => {
// Multer errors are automatically handled
// Custom validation errors are thrown as MulterError
});

// Error handling middleware
app.use((error, req, res, next) => {
if (error instanceof MulterError) {
switch (error.code) {
case 'LIMIT_FILE_SIZE':
return res.status(400).json({ error: 'File too large' });
case 'LIMIT_UNEXPECTED_FILE':
return res.status(400).json({ error: 'Invalid file type' });
default:
return res.status(400).json({ error: error.message });
}
}
next(error);
});
`

Memory vs Disk Storage

$3

`typescript
const memoryUploader = createMemoryUploader();
// Access via req.file.buffer
`

$3

`typescript
const diskUploader = createDiskUploader('./uploads');
// Access via req.file.path
`

API Reference

$3

#### Methods

- single(fieldName: string) - Handle single file upload
- array(fieldName: string, maxCount?: number) - Handle multiple files (same field)
- fields(fields: multer.Field[]) - Handle multiple fields
- any() - Handle any files
- none() - No files expected
- validateFile(file: Express.Multer.File) - Validate file manually
- getFileInfo(file: Express.Multer.File) - Get detailed file information
- deleteFile(filename: string) - Delete file (disk storage only)
- fileExists(filename: string) - Check if file exists (disk storage only)
- getFilePath(filename: string) - Get file path (disk storage only)
- getUploadStats() - Get upload directory statistics
- getConfig() - Get current configuration

$3

- createDiskUploader(uploadDir: string, config?: Partial)
- createMemoryUploader(config?: Partial)
- createImageUploader(uploadDir?: string)
- createAudioUploader(uploadDir?: string)

TypeScript Support

The package is fully typed and exports all necessary interfaces:

`typescript
import {
UploadService,
UploadConfig,
FileValidationResult,
MulterError
} from 'multer-utility';
``

Author

[SURAJ] — suraj222615@gmail.com
GitHub: https://github.com/suraj-o

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT © [Suraj]

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Made with ❤️ and TypeScript