svelte-firebase-upload

File upload manager for Svelte 5 + Firebase Storage. Concurrent uploads, resumable transfers, file validation, and a Dropbox-style upload panel — zero extra dependencies.

Install

npm install svelte-firebase-upload firebase

Quick Start

<script>
  import { initializeApp } from 'firebase/app';
  import { getStorage } from 'firebase/storage';
  import { FirebaseUploadManager, UploadPanel, UploadDropZone } from 'svelte-firebase-upload';

  const app = initializeApp({ /* your config */ });
  const storage = getStorage(app);

  const manager = new FirebaseUploadManager({
    maxConcurrentUploads: 3,
    autoStart: true
  });

  manager.setStorage(storage);

  let showPanel = $state(true);
</script>

<UploadDropZone uploadManager={manager} accept="image/*,.pdf" />
<UploadPanel uploadManager={manager} bind:visible={showPanel} />

Features

• Concurrent uploads with configurable concurrency limits
• Resumable transfers with chunk-based recovery
• File validation — size limits, type checks, duplicate detection, security scanning
• Dropbox-style UI — floating panel with progress, tabs, per-file actions
• Drag & drop zone — standalone component with file filtering
• Error handling — stall detection, toast notifications, retry with backoff
• Network awareness — monitors connection quality, adapts to conditions
• Bandwidth throttling — adaptive rate limiting
• Plugin system — extensible hooks for every upload lifecycle event
• SSR safe — all browser APIs guarded for SvelteKit
• Themeable — CSS custom properties for full visual control
• TypeScript — fully typed API

Components

UploadPanel

Floating panel that shows upload progress, errors, and per-file actions.

<UploadPanel
  uploadManager={manager}
  bind:visible={showPanel}
  position="bottom-right"
  onerror={(item, error) => console.log('Failed:', item.file.name)}
/>

Prop	Type	Default	Description
uploadManager	FirebaseUploadManager	required	Manager instance
visible	boolean	true	Bindable show/hide
position	'bottom-right' | 'bottom-left'	'bottom-right'	Panel position
onerror	(item, error) => void	—	Error callback

UploadDropZone

Drag & drop area with click-to-browse. Supports custom content via slot.

<UploadDropZone
  uploadManager={manager}
  accept="image/*,.pdf"
  path="user-uploads/"
  maxSize={10 * 1024 * 1024}
/>

Prop	Type	Default	Description
uploadManager	FirebaseUploadManager	required	Manager instance
accept	string	''	File type filter
multiple	boolean	true	Allow multiple files
maxSize	number	—	Max file size (bytes)
path	string	'uploads/'	Storage directory
disabled	boolean	false	Disable interaction

Manager API

const manager = new FirebaseUploadManager({
  maxConcurrentUploads: 5,  // default: 5
  chunkSize: 5 * 1024 * 1024,  // default: 5MB
  retryAttempts: 3,  // default: 3
  retryDelay: 1000,  // default: 1000ms
  autoStart: true,  // default: false
  enableSmartScheduling: true  // default: false
});

manager.setStorage(storage);

// Add files
await manager.addFiles(fileList, { path: 'photos/' });

// Control
await manager.start();
await manager.pause();
await manager.resume();
await manager.stop();

// Validation
const results = await manager.validateFiles(files, {
  maxSize: 10 * 1024 * 1024,
  allowedTypes: ['image/*', '.pdf']
});

// State (all reactive with $state)
manager.totalProgress  // 0-100
manager.currentSpeed   // bytes/sec
manager.successCount
manager.failureCount
manager.isProcessing
manager.queue
manager.failed
manager.completed

Plugins

import { LoggingPlugin, AnalyticsPlugin } from 'svelte-firebase-upload';

await manager.registerPlugin(new LoggingPlugin({ logLevel: 'info' }));
await manager.registerPlugin(new AnalyticsPlugin());

Built-in presets: LoggingPlugin, AnalyticsPlugin, FileProcessingPlugin, ValidationEnhancementPlugin, QueueOptimizationPlugin.

Theming

Override CSS custom properties to match your design:

:root {
  --sfu-panel-bg: #ffffff;
  --sfu-panel-border: #e5e7eb;
  --sfu-panel-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  --sfu-text-primary: #111827;
  --sfu-text-secondary: #6b7280;
  --sfu-progress-bg: #e5e7eb;
  --sfu-progress-fill: #3b82f6;
  --sfu-success: #22c55e;
  --sfu-error: #ef4444;
  --sfu-warning: #f59e0b;
  --sfu-radius: 12px;
  --sfu-font-family: system-ui, -apple-system, sans-serif;
}

Firebase Setup

Your storage bucket needs CORS configured for local development:

[{
  "origin": ["http://localhost:5173"],
  "method": ["GET", "POST", "PUT", "DELETE", "HEAD"],
  "maxAgeSeconds": 3600,
  "responseHeader": ["Content-Type", "Authorization", "Content-Length", "User-Agent", "x-goog-resumable"]
}]

Apply with: gcloud storage buckets update gs://YOUR_BUCKET --cors-file=cors.json

License

MIT