Deno v1.34.2 — Release Notes & Engineering Impact

Source available — automated, not human-reviewed

Component: deno · Channel: stable. Automated analysis, not a compatibility certification. How this works.

Analysis updated: 2026-11-01.

Compatibility not verified — check source notes

📄 .MD

✨ Features 1 ⚡ Improvements 6 🔧 Bug Fixes 6

⚡ Executive Summary (TL;DR)

Deno v1.34.2. Source highlight: fix: do not show cache initialization errors if stderr is piped (#18920)

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Who Does This Impact? (Role-Based Analysis)

💻 Software Engineers & Devs

Check the source notes against the package and APIs you use before upgrading.

📊 Product & Engineering Leads

Use the documented changes to assess relevance to your product; release frequency alone is not a quality measure.

⚙️ DevOps & Security

Verify the target version, runtime requirements and rollback procedure in the official documentation.

✨ New Features & Capabilities (1)

perf(ext/http): Add a sync phase to http serving (#19321)

⚡ Performance & Enhancements (6)

perf(cli): conditionally load typescript declaration files (#19392)
perf(ext/http): Migrate op_http_get_request_headers to v8::Array (#19354)
perf(ext/http): Migrate op_http_get_request_method_and_url to v8::Array
perf(ext/http): Use flat list of headers for multiple set/get methods (#19336)
perf(ext/websocket): Make send sync for non-stream websockets (#19376)
perf(ext/websocket): Reduce GC pressure & monomorpize op_ws_next_event

🔧 Bug Fixes & Patches (6)

fix: do not show cache initialization errors if stderr is piped (#18920)
fix: upgrade to deno_ast 0.27 (#19375)
fix(cli): formatting bench with colors (#19323)
fix(ext/console): fix inspecting large ArrayBuffers (#19373)
fix(ext/crypto): fix JWK import of Ed25519 (#19279)
fix(ext/web): Copy EventTarget list before dispatch (#19360)

📄 View Raw Release Notes (Original Developer Log)

### 1.34.2 / 2023.06.08 - fix: do not show cache initialization errors if stderr is piped (#18920) - fix: upgrade to deno_ast 0.27 (#19375) - fix(cli): formatting bench with colors (#19323) - fix(ext/console): fix inspecting large ArrayBuffers (#19373) - fix(ext/crypto): fix JWK import of Ed25519 (#19279) - fix(ext/web): Copy EventTarget list before dispatch (#19360) - fix(ext/websocket): Close socket on bad string data (#19424) - fix(kv) run sqlite transactions via spawn_blocking (#19350) - fix(napi): don't panic if symbol can't be found (#19397) - fix(node): add missing process.reallyExit method (#19326) - fix(node): Added base implementation of FileHandle (#19294) - fix(node): don't close stdio streams (#19256) - fix(node): FileHandle.close() (#19357) - fix(node): FileHandle.read() (#19359) - fix(node): FileHandle.write() (#19385) - fix(node): map stdio [0, 1, 2] to "inherit" (#19352) - fix(node): Very basic node:http2 support (#19344) - fix(node): proper url handling (#19340) - fix(repl): correctly print string exception (#19391) - fix(runtime): add missing SIGIOT alias to SIGABRT (#19333) - perf(cli): conditionally load typescript declaration files (#19392) - perf(ext/http): Add a sync phase to http serving (#19321) - perf(ext/http): Migrate op_http_get_request_headers to v8::Array (#19354) - perf(ext/http): Migrate op_http_get_request_method_and_url to v8::Array (#19355) - perf(ext/http): Use flat list of headers for multiple set/get methods (#19336) - perf(ext/websocket): Make send sync for non-stream websockets (#19376) - perf(ext/websocket): Reduce GC pressure & monomorpize op_ws_next_event (#19405) - perf(ext/websocket): monomorphize code (#19394) - perf(http): avoid flattening http headers (#19384) - perf: optimize RegExp usage in JS (#19364) - perf: use sendto syscalls (#19414)

← Older Version Deno v1.34.1 Newer Version → Deno v1.34.3