src/views/Header/HeaderStyleInterpolator.js
function forLeftButton(props) {
  const { position, scene, scenes } = props;
  const interpolate = getSceneIndicesForInterpolationInputRange(props);

  if (!interpolate) return { opacity: 0 };

  const { first, last } = interpolate;
  const index = scene.index;

  return {
    opacity: position.interpolate({
      inputRange: [
        first,
        first + Math.abs(index - first) / 2,
        index,
        last - Math.abs(last - index) / 2,
        last,
      ],
      outputRange: [0, 0.5, 1, 0.5, 0],
    }),
  };
}
function forLeftButton(props) {
  const { position, scene, scenes } = props;
  const interpolate = getSceneIndicesForInterpolationInputRange(props);

  if (!interpolate) return { opacity: 0 };

  const { first, last } = interpolate;
  const index = scene.index;

  return {
    opacity: position.interpolate({
      inputRange: [
        first,
        first + Math.abs(index - first) / 2,
        index,
        last - Math.abs(last - index) / 2,
        last,
      ],
      outputRange: [0, 0.5, 1, 0.5, 0],
    }),
  };
}
function forLeftButton ( props ) { const { position , scene , scenes } = props ; const interpolate = getSceneIndicesForInterpolationInputRange ( props ) ; if ( ! interpolate ) return { opacity : 0 } ; const { first , last } = interpolate ; const index = scene . index ; return { opacity : position . interpolate ( { inputRange : [ first , first + Math . abs ( index - first ) / 2 , index , last - Math . abs ( last - index ) / 2 , last , ] , outputRange : [ 0 , 0.5 , 1 , 0.5 , 0 ] , } ) , } ; }
iOS UINavigationController style interpolators
iOS UINavigationController style interpolators