Summary
Follow-up to #227. response.blob() (in crates/perry-stdlib/src/fetch.rs, immediately below the arrayBuffer() fix that landed via #232) has the same metadata-only-stub bug: resp.body is consumed only for .len(), then the resolved value is a 2-field stub object { size, type } with no actual byte storage. Any user code trying to read bytes out of a Blob sees nothing.
Why this is broader scope than #227
response.arrayBuffer() could be fixed by returning a real BufferHeader because the user-side consumers (new Uint8Array(buf) / Buffer.from(buf)) are already wired through the buffer registry. Blob is a distinct JS type with its own surface that needs to land first:
blob.arrayBuffer(): Promise<ArrayBuffer>blob.text(): Promise<string>blob.bytes(): Promise<Uint8Array> (newer, but increasingly common)blob.slice(start?, end?, type?): Blobblob.stream(): ReadableStream (separate gap; depends on stream impl)
Each method needs:
- A runtime symbol exported from
perry-stdlib (probably keyed off a BLOB_REGISTRY similar to FETCH_RESPONSES).
- A codegen dispatch row in
crates/perry-codegen/src/lower_call.rs routing blob.<method>() to the runtime symbol — mirroring how the arrayBuffer / clone / headers methods are routed for Response.
Repro
```ts
const res = await fetch("https://example.com/some.bin\");
const blob = await res.blob();
console.log("size:", blob.size, "type:", blob.type); // correct
const buf = await blob.arrayBuffer(); // currently undefined / no-op
const bytes = new Uint8Array(buf);
console.log("actual length:", bytes.length); // 0
```
Workaround in the meantime
Skip `blob()` entirely and call `response.arrayBuffer()` directly — that path now returns real bytes (#232).
Pointers
Summary
Follow-up to #227.
response.blob()(incrates/perry-stdlib/src/fetch.rs, immediately below thearrayBuffer()fix that landed via #232) has the same metadata-only-stub bug:resp.bodyis consumed only for.len(), then the resolved value is a 2-field stub object{ size, type }with no actual byte storage. Any user code trying to read bytes out of aBlobsees nothing.Why this is broader scope than #227
response.arrayBuffer()could be fixed by returning a realBufferHeaderbecause the user-side consumers (new Uint8Array(buf)/Buffer.from(buf)) are already wired through the buffer registry.Blobis a distinct JS type with its own surface that needs to land first:blob.arrayBuffer(): Promise<ArrayBuffer>blob.text(): Promise<string>blob.bytes(): Promise<Uint8Array>(newer, but increasingly common)blob.slice(start?, end?, type?): Blobblob.stream(): ReadableStream(separate gap; depends on stream impl)Each method needs:
perry-stdlib(probably keyed off aBLOB_REGISTRYsimilar toFETCH_RESPONSES).crates/perry-codegen/src/lower_call.rsroutingblob.<method>()to the runtime symbol — mirroring how thearrayBuffer/clone/headersmethods are routed forResponse.Repro
```ts
const res = await fetch("https://example.com/some.bin\");
const blob = await res.blob();
console.log("size:", blob.size, "type:", blob.type); // correct
const buf = await blob.arrayBuffer(); // currently undefined / no-op
const bytes = new Uint8Array(buf);
console.log("actual length:", bytes.length); // 0
```
Workaround in the meantime
Skip `blob()` entirely and call `response.arrayBuffer()` directly — that path now returns real bytes (#232).
Pointers