Add JavaScript API (WebAssembly) for Google MedAsr model

[csukuangfj]

Summary by CodeRabbit

• New Features

  • Added support for MedASR CTC model, enabling offline speech-to-text recognition capabilities.

• Tests

  • Introduced test scripts demonstrating MedASR model decoding with sample audio files.

• Documentation

  • Updated guides with MedASR model setup instructions and execution examples.

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[coderabbitai]

Note

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CodeRabbit has detected other AI code review bot(s) in this pull request and will avoid duplicating their findings in the review comments. This may lead to a less comprehensive review.

📝 Walkthrough

Walkthrough

Adds support for MedASR (Medical Speech Recognition) CTC models to sherpa-onnx by introducing a new Node.js test script for offline MedASR decoding, corresponding documentation, and WASM/JavaScript configuration structures with memory handling. CI tests are extended to validate MedASR and other model scenarios. A lexicon entry is removed from the TTS test configuration.

Changes

Cohort / File(s)	Summary
CI & Test Scripts .github/scripts/test-nodejs-npm.sh	Extended test workflow to download, extract, and run tests for MedASR CTC int8 model and omnilingual 1600-language CTC model, with cleanup steps for both scenarios.
Node.js Examples nodejs-examples/test-offline-medasr-ctc.js	New offline MedASR recognizer test script that configures a MedASR CTC int8 model, reads WAV input, performs decoding, and outputs recognized text.
Documentation nodejs-examples/README.md	Added documentation sections describing MedASR CTC model decoding workflow, including model tarball reference and example run commands.
TTS Configuration nodejs-examples/test-offline-tts-matcha-en.js	Removed unused lexicon configuration entry from offline TTS Matcha model setup.
WASM ASR Config wasm/asr/sherpa-onnx-asr.js	Introduced initSherpaOnnxOfflineMedAsrCtcModelConfig() function and extended offline model configuration pipeline to handle MedASR memory allocation, heap sizing, and config object composition.
WASM Node.js Binding wasm/nodejs/sherpa-onnx-wasm-nodejs.cc	Added static_assert validation for SherpaOnnxOfflineMedAsrCtcModelConfig size and integrated MedASR config output to PrintOfflineRecognizerConfig.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• Fix wasm for kws #2535 — Extends aggregate model-config size assertion to include additional model config type via similar static_assert pattern.
• Add JavaScript (WebAssembly) API for Omnilingual ASR CTC models #2781 — Adds omnilingual ASR CTC support with parallel init/struct handling in WASM and Node.js test script additions.
• export omniASR_CTC_1B from https://github.com/facebookresearch/omnilingual-asr #2788 — Provides backend and export handling for omnilingual models, complementing test scripts added here.

Poem

🐰 A rabbit hops through medical speech,
MedASR models now within reach,
WASM configs dance with careful care,
Tests validated, warnings laid bare,
Recognition flows, healing's made fair! 🏥✨

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding JavaScript/WebAssembly API support for Google MedAsr model, which is evident from the new files (test-offline-medasr-ctc.js), WASM bindings (sherpa-onnx-asr.js), C++ integration (sherpa-onnx-wasm-nodejs.cc), and documentation updates.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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📜 Recent review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 13b8b84 and 462425d.

📒 Files selected for processing (6)

• .github/scripts/test-nodejs-npm.sh
• nodejs-examples/README.md
• nodejs-examples/test-offline-medasr-ctc.js
• nodejs-examples/test-offline-tts-matcha-en.js
• wasm/asr/sherpa-onnx-asr.js
• wasm/nodejs/sherpa-onnx-wasm-nodejs.cc

💤 Files with no reviewable changes (1)

• nodejs-examples/test-offline-tts-matcha-en.js

🧰 Additional context used

🧬 Code graph analysis (2)

wasm/asr/sherpa-onnx-asr.js (1)

nodejs-examples/test-offline-medasr-ctc.js (1)

• config (10-17)

wasm/nodejs/sherpa-onnx-wasm-nodejs.cc (1)

wasm/asr/sherpa-onnx-asr.js (1)

• medasr (1169-1170)

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[gemini-code-assist]

Summary of Changes

Hello @csukuangfj, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly expands the capabilities of the JavaScript (WebAssembly) API by integrating support for the Google MedAsr model. This addition allows developers to leverage the MedAsr model for offline speech recognition directly within Node.js applications. The changes encompass the necessary configuration handling, a practical usage example, and updates to the automated testing pipeline to ensure robustness.

Highlights

• Google MedAsr Model Support: Introduced a new JavaScript (WebAssembly) API for the Google MedAsr model, enabling its use within Node.js environments.
• New Node.js Example: Added a new Node.js example, test-offline-medasr-ctc.js, demonstrating how to perform offline speech recognition using the MedAsr CTC model.
• CI Script Update: The CI script for Node.js NPM tests has been updated to include downloading, testing, and cleaning up the MedAsr model, ensuring continuous validation of the new functionality.
• WebAssembly Configuration Integration: Modified the core WebAssembly JavaScript and C++ files to properly handle the configuration and memory management for the new MedAsr model.

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[gemini-code-assist]

Code Review

This pull request adds JavaScript API support for the Google MedASR model, including a new Node.js example, updates to the CI test script, and necessary changes to the WebAssembly bindings. The implementation is consistent with the existing codebase structure. My review includes a couple of suggestions for improving script efficiency and code cleanliness in the new example file. Overall, the changes look good.

[gemini-code-assist]

For efficiency and simplicity, you can download and extract the model in a single command by piping curl to tar. This avoids writing the compressed archive to disk.

Suggested change

	curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-medasr-ctc-en-int8-2025-12-25.tar.bz2
	tar xvf sherpa-onnx-medasr-ctc-en-int8-2025-12-25.tar.bz2
	rm sherpa-onnx-medasr-ctc-en-int8-2025-12-25.tar.bz2
	curl -SL https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-medasr-ctc-en-int8-2025-12-25.tar.bz2 | tar xvjf -

[gemini-code-assist]

These modules (fs, Readable from stream, and wav) are imported but not used in this file. It's good practice to remove unused imports to keep the code clean and reduce the module's dependency footprint.