SpeechRecognitionResult.length

The length read-only property of the SpeechRecognitionResult interface returns the length of the "array" — the number of SpeechRecognitionAlternative objects contained in the result (also referred to as "n-best alternatives".)

The number of alternatives contained in the result depends on what the SpeechRecognition.maxAlternatives property was set to when the speech recognition was first initiated.

Value

A number.

Examples

This code is excerpted from our Speech color changer example.

recognition.onresult = (event) => {
  // The SpeechRecognitionEvent results property returns a SpeechRecognitionResultList object
  // The SpeechRecognitionResultList object contains SpeechRecognitionResult objects.
  // It has a getter so it can be accessed like an array
  // The first [0] returns the SpeechRecognitionResult at position 0.
  // Each SpeechRecognitionResult object contains SpeechRecognitionAlternative objects
  // that contain individual results.
  // These also have getters so they can be accessed like arrays.
  // The second [0] returns the SpeechRecognitionAlternative at position 0.
  // We then return the transcript property of the SpeechRecognitionAlternative object
  const color = event.results[0][0].transcript;
  diagnostic.textContent = `Result received: ${color}.`;
  bg.style.backgroundColor = color;

  console.log(event.results[0].length);
}

Specifications

Specification
Web Speech API
# dom-speechrecognitionresult-length

Browser compatibility

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See also