stream-chat-react-native-core/src/components/MessageInput/utils/normalizeAudioLevel.ts

The official React Native and Expo components for Stream Chat, a service for building chat applications

/**
 * Utility function to normalize the audio level.
 */
export const normalizeAudioLevel = (value: number, lowerBound: number) => {
  // For Native CLI, the lower bound is around -50
  const upperBound = 0;

  const delta = upperBound - lowerBound;

  // In Native CLI Android, the value is undefined for loud audio
  if (value === undefined) {
    return 1;
  }

  if (value < lowerBound) {
    return 0;
  } else if (value >= upperBound) {
    return 1;
  } else {
    return Math.abs((value - lowerBound) / delta);
  }
};