Add keyword spotting API for node-addon-api (#877)

nodejs-addon-examples/test_keyword_spotter_transducer_microphone.js

@@ -0,0 +1,74 @@
+// Copyright (c)  2023-2024  Xiaomi Corporation (authors: Fangjun Kuang)
+//
+const portAudio = require('naudiodon2');
+// console.log(portAudio.getDevices());
+
+const sherpa_onnx = require('sherpa-onnx-node');
+
+function createKeywordSpotter() {
+  const config = {
+    'featConfig': {
+      'sampleRate': 16000,
+      'featureDim': 80,
+    },
+    'modelConfig': {
+      'transducer': {
+        'encoder':
+            './sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/encoder-epoch-12-avg-2-chunk-16-left-64.onnx',
+        'decoder':
+            './sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/decoder-epoch-12-avg-2-chunk-16-left-64.onnx',
+        'joiner':
+            './sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/joiner-epoch-12-avg-2-chunk-16-left-64.onnx',
+      },
+      'tokens':
+          './sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/tokens.txt',
+      'numThreads': 2,
+      'provider': 'cpu',
+      'debug': 1,
+    },
+    'keywordsFile':
+        './sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01/keywords.txt',
+  };
+
+  return new sherpa_onnx.KeywordSpotter(config);
+}
+
+const kws = createKeywordSpotter();
+const stream = kws.createStream();
+
+let lastText = '';
+let segmentIndex = 0;
+
+const ai = new portAudio.AudioIO({
+  inOptions: {
+    channelCount: 1,
+    closeOnError: true,  // Close the stream if an audio error is detected, if
+                         // set false then just log the error
+    deviceId: -1,  // Use -1 or omit the deviceId to select the default device
+    sampleFormat: portAudio.SampleFormatFloat32,
+    sampleRate: kws.config.featConfig.sampleRate
+  }
+});
+
+const display = new sherpa_onnx.Display(50);
+
+ai.on('data', data => {
+  const samples = new Float32Array(data.buffer);
+
+  stream.acceptWaveform(
+      {sampleRate: kws.config.featConfig.sampleRate, samples: samples});
+
+  while (kws.isReady(stream)) {
+    kws.decode(stream);
+  }
+
+  const keyword = kws.getResult(stream).keyword
+  if (keyword != '') {
+    display.print(segmentIndex, keyword);
+    segmentIndex += 1;
+  }
+});
+
+ai.start();
+console.log('Started! Please speak.')
+console.log(`Only words from ${kws.config.keywordsFile} can be recognized`)