demo · v132

Streaming write — chunked, with progress

The classic File System Access demo opens a file then dumps everything at once. The real win is streaming: createWritable() returns a WritableStream that accepts chunks and reports progress. Pick a size, save to disk, and watch the bytes go down.

checking createWritable…
0 / 0 bytes

the code

const handle = await showSaveFilePicker({ suggestedName: "blob.bin" });
const writable = await handle.createWritable();
for (let off = 0; off < total; off += chunkSize) {
  await writable.write(makeChunk(chunkSize));
  reportProgress(off);
}
await writable.close();

see also