Add VAD and keyword spotting for the Node package with WebAssembly (#1286)

wasm/nodejs/CMakeLists.txt

@@ -49,6 +49,32 @@ set(exported_functions
   SherpaOnnxDestroyKeywordSpotter
   SherpaOnnxGetKeywordResult
   SherpaOnnxIsKeywordStreamReady
+  # VAD
+  SherpaOnnxCreateCircularBuffer
+  SherpaOnnxDestroyCircularBuffer
+  SherpaOnnxCircularBufferPush
+  SherpaOnnxCircularBufferGet
+  SherpaOnnxCircularBufferFree
+  SherpaOnnxCircularBufferPop
+  SherpaOnnxCircularBufferSize
+  SherpaOnnxCircularBufferHead
+  SherpaOnnxCircularBufferReset
+  SherpaOnnxCreateVoiceActivityDetector
+  SherpaOnnxDestroyVoiceActivityDetector
+  SherpaOnnxVoiceActivityDetectorAcceptWaveform
+  SherpaOnnxVoiceActivityDetectorEmpty
+  SherpaOnnxVoiceActivityDetectorDetected
+  SherpaOnnxVoiceActivityDetectorPop
+  SherpaOnnxVoiceActivityDetectorClear
+  SherpaOnnxVoiceActivityDetectorFront
+  SherpaOnnxDestroySpeechSegment
+  SherpaOnnxVoiceActivityDetectorReset
+  SherpaOnnxVoiceActivityDetectorFlush
+  #
+  SherpaOnnxFileExists
+  SherpaOnnxReadWave
+  SherpaOnnxFreeWave
+  SherpaOnnxWriteWave
 )
 
 
@@ -82,6 +108,8 @@ install(
   ${CMAKE_SOURCE_DIR}/wasm/asr/sherpa-onnx-asr.js
   ${CMAKE_SOURCE_DIR}/wasm/tts/sherpa-onnx-tts.js
   ${CMAKE_SOURCE_DIR}/wasm/kws/sherpa-onnx-kws.js
+  ${CMAKE_SOURCE_DIR}/wasm/vad/sherpa-onnx-vad.js
+  ${CMAKE_SOURCE_DIR}/wasm/nodejs/sherpa-onnx-wave.js
     "$<TARGET_FILE_DIR:sherpa-onnx-wasm-nodejs>/sherpa-onnx-wasm-nodejs.js"
     "$<TARGET_FILE_DIR:sherpa-onnx-wasm-nodejs>/sherpa-onnx-wasm-nodejs.wasm"
   DESTINATION

wasm/nodejs/sherpa-onnx-wave.js

@@ -0,0 +1,57 @@
+// return an object
+// {
+//   samples: a float32 array
+//   sampleRate: an integer
+// }
+function readWave(filename, Module) {
+  const filenameLen = Module.lengthBytesUTF8(filename) + 1;
+  const pFilename = Module._malloc(filenameLen);
+  Module.stringToUTF8(filename, pFilename, filenameLen);
+
+  const w = Module._SherpaOnnxReadWave(pFilename);
+  Module._free(pFilename);
+
+
+  const samplesPtr = Module.HEAP32[w / 4] / 4;
+  const sampleRate = Module.HEAP32[w / 4 + 1];
+  const numSamples = Module.HEAP32[w / 4 + 2];
+
+  const samples = new Float32Array(numSamples);
+  for (let i = 0; i < numSamples; i++) {
+    samples[i] = Module.HEAPF32[samplesPtr + i];
+  }
+
+  Module._SherpaOnnxFreeWave(w);
+
+
+  return {samples: samples, sampleRate: sampleRate};
+}
+
+// data is an object
+// {
+//   samples: a float32 array
+//   sampleRate: an integer
+// }
+function writeWave(filename, data, Module) {
+  const pSamples =
+      Module._malloc(data.samples.length * data.samples.BYTES_PER_ELEMENT);
+  Module.HEAPF32.set(data.samples, pSamples / data.samples.BYTES_PER_ELEMENT);
+
+  const filenameLen = Module.lengthBytesUTF8(filename) + 1;
+  const pFilename = Module._malloc(filenameLen);
+  Module.stringToUTF8(filename, pFilename, filenameLen);
+
+  Module._SherpaOnnxWriteWave(
+      pSamples, data.samples.length, data.sampleRate, pFilename);
+
+  Module._free(pFilename);
+  Module._free(pSamples);
+}
+
+if (typeof process == 'object' && typeof process.versions == 'object' &&
+    typeof process.versions.node == 'string') {
+  module.exports = {
+    readWave,
+    writeWave,
+  };
+}