Tar
Tape Archive
A Unix file format that bundles multiple files into a single archive without compression, often paired with gzip.
技術的詳細
File tar reduces storage and transmission size. DEFLATE (used in ZIP and gzip) combines LZ77 dictionary coding with Huffman coding. Brotli (RFC 7932) achieves 15-25% better compression than gzip for text content and is supported by all modern browsers for HTTP compression. Zstandard (zstd) offers tunable compression levels from fast (comparable to lz4) to high (comparable to LZMA). For files already in compressed formats (JPEG, MP3, ZIP), re-compression provides negligible benefit and may slightly increase file size.
例
```javascript
// Create ZIP archive in browser (using JSZip)
const zip = new JSZip();
zip.file('readme.txt', 'Hello World');
zip.file('data/report.csv', csvContent);
const blob = await zip.generateAsync({
type: 'blob',
compression: 'DEFLATE',
compressionOptions: { level: 6 },
});
saveAs(blob, 'archive.zip');
```