feat(node): add clone() support to ImpitResponse#419
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barjin merged 6 commits intoapify:masterfrom Mar 24, 2026
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Implement Response.clone() on ImpitResponse using ReadableStream.tee() to split the body into two independent streams. The original response's body methods are re-bound to one stream; the clone is a standard Response backed by the other. - Streaming preserved (no eager buffering) - Charset-aware text() preserved on original via decodeBuffer - Throws TypeError on double clone or clone after body consumed - Clone returns standard Response (with url set via defineProperty)
- Add bodyConsumed flag: clone() after body consumption now throws
a clear TypeError ("body has already been consumed") instead of a
cryptic ReadableStream error
- Move cloned=true after successful tee() to avoid side effects on
failure
- Change dts-header from class to interface: TypeScript does not
merge duplicate class declarations, causing TS2300 when prepended
to the auto-generated index.d.ts
- Separate error messages: "body has already been consumed" vs
"Response has already been cloned"
- Add tests: arrayBuffer on both, read-original-first order, non-200
status preservation, strict TypeError + message assertion
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- Override body getter after tee() so response.body returns the delegate's stream instead of the original locked stream - Remove single-clone restriction (cloned flag) to match Fetch spec - Add markConsumed + configurable to re-patched methods so consumption tracking and subsequent clones work correctly - Add tests: multiple clones, body streaming after clone
barjin
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Thank you @privatenumber !
I just cleaned up some rough edges (e.g., moving the clone() declaration to the Rust code or making the text decoding work on the cloned response as well). Otherwise I am happy with the proposed changes.
Thanks again!
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Summary
Implements
Response.clone()onImpitResponseusingReadableStream.tee(), making impit compatible with libraries like ky that callresponse.clone()internally.Approach
When
.clone()is called:this.body.tee()splits the underlyingReadableStreaminto two independent streams (synchronous, no eager buffering).bodygetter and body methods (text,json,arrayBuffer,bytes) are re-patched to read from one streamResponseis returned as the clone, backed by the other streamMultiple clones are supported (matching the Fetch spec) — each call tees the current branch, so the original and all clones can be read independently.
Charset-aware
text()decoding is preserved on the original viadecodeBuffer. The clone uses standardResponse.text()(UTF-8).Throws
TypeErroron clone after body consumption, matching Fetch API semantics.Changes
index.wrapper.js— addclone()in#wrapResponse, re-patch.bodygetter and body methods withconfigurable: trueso subsequent clones workdts-header.d.ts— addclone(): ResponsetoImpitResponsevia declaration mergingtest/basics.test.ts— tests covering: return type, url/header preservation, independent body reads, text() on both, multiple clones, body streaming after clone, clone-after-consume error, arrayBuffer on both, read ordering, non-200 status