import React from "react";import { Animated, Easing, SectionList, StatusBar, StyleSheet, Text,
      TouchableOpacity, View } from "react-native";const App = () => {
  let opacity = new Animated.Value(0);
  const animate = easing => {
    opacity.setValue(0);
    Animated.timing(opacity, {
      toValue: 1,
      duration: 1200,
      easing
    }).start();};
  const size = opacity.interpolate({
    inputRange: [0, 1],
    outputRange: [0, 80]});
  const animatedStyles = [
    styles.box,
    {opacity,
      width: size,
      height: size}];
  return (
    <View style={styles.container}>
      <StatusBar hidden={true} />
      <Text style={styles.title}>
        Press rows below to preview the Easing!
      </Text>
      <View style={styles.boxContainer}>
        <Animated.View style={animatedStyles} />
      </View>
      <SectionList style={styles.list} sections={SECTIONS}
                         keyExtractor={(item) => item.title}
                         renderItem={({ item }) => (
          <TouchableOpacity
            onPress={() => animate(item.easing)}
            style={styles.listRow}>
            <Text>{item.title}</Text>
          </TouchableOpacity>
        )}
        renderSectionHeader={({ section: { title } }) => (
          <Text style={styles.listHeader}>{title}</Text>
        )}
      />
    </View>
  );};const SECTIONS = [
  {title: "Predefined animations",
    data: [
      { title: "Bounce", easing: Easing.bounce },
      { title: "Ease", easing: Easing.ease },
      { title: "Elastic", easing: Easing.elastic(4) }]},
  {title: "Standard functions",
    data: [
      { title: "Linear", easing: Easing.linear },
      { title: "Quad", easing: Easing.quad },
      { title: "Cubic", easing: Easing.cubic } ]},
  {title: "Additional functions",
    data: [{title: "Bezier",
                easing: Easing.bezier(0, 2, 1, -1)},
      { title: "Circle", easing: Easing.circle },
      { title: "Sin", easing: Easing.sin },
      { title: "Exp", easing: Easing.exp }]},
  {title: "Combinations",
    data: [{title: "In + Bounce",
               easing: Easing.in(Easing.bounce)},
              {title: "Out + Exp",
               easing: Easing.out(Easing.exp)},
        {title: "InOut + Elastic",
                easing: Easing.inOut(Easing.elastic(1))}]}];const styles = StyleSheet.create({
  container: { flex: 1, backgroundColor: "#20232a"},
  title: { marginTop: 10, textAlign: "center", color: "#61dafb"},
  boxContainer: { height: 160, alignItems: "center"},
  box: { marginTop: 32, borderRadius: 4, backgroundColor: "#61dafb"},
  list: {backgroundColor: "#fff" },
  listHeader: {
    paddingHorizontal: 8,
    paddingVertical: 4,
    backgroundColor: "#f4f4f4",
    color: "#999",
    fontSize: 12,
    textTransform: "uppercase"
  },
  listRow: { padding: 8 }});export default App;