CollapseExpand.js

let CollapseExpand = (index, position) => {
  const inputRange = [index - 1, index, index + 1];
  const opacity = position.interpolate({
    inputRange,
    outputRange: [0, 1, 1],
  });

  const scaleY = position.interpolate({
    inputRange,
    outputRange: ([0, 1, 1]),
  });

  return {
    opacity,
    transform: [
      { scaleY }
    ]
  };
};