types/web-speech.d.ts

/**
 * Web Speech API type declarations.
 * These are not included in the default TypeScript DOM lib.
 */

interface SpeechRecognitionEvent extends Event {
  readonly results: SpeechRecognitionResultList;
  readonly resultIndex: number;
}

interface SpeechRecognitionResultList {
  readonly length: number;
  item(index: number): SpeechRecognitionResult;
  [index: number]: SpeechRecognitionResult;
}

interface SpeechRecognitionResult {
  readonly length: number;
  readonly isFinal: boolean;
  item(index: number): SpeechRecognitionAlternative;
  [index: number]: SpeechRecognitionAlternative;
}

interface SpeechRecognitionAlternative {
  readonly transcript: string;
  readonly confidence: number;
}

interface SpeechRecognition extends EventTarget {
  continuous: boolean;
  interimResults: boolean;
  lang: string;
  onresult: ((event: SpeechRecognitionEvent) => void) | null;
  onend: (() => void) | null;
  onerror: ((event: Event) => void) | null;
  start(): void;
  stop(): void;
  abort(): void;
}

interface SpeechRecognitionConstructor {
  new (): SpeechRecognition;
}

interface Window {
  SpeechRecognition?: SpeechRecognitionConstructor;
  webkitSpeechRecognition?: SpeechRecognitionConstructor;
}