我克隆了一个前端的todo应用程序，点击“工作”或“旅行”按钮，它会自动显示适合该按钮的列表。

import { StatusBar } from "expo-status-bar";
import React, { useEffect, useState } from "react";
import {
  StyleSheet,
  Text,
  View,
  TouchableOpacity,
  TextInput,
  ScrollView,
} from "react-native";
import AsyncStorage from "@react-native-async-storage/async-storage";
import { theme } from "./colors";

const STORAGE_KEY = "@toDos";

export default function App() {
  const [working, setWorking] = useState(true);
  const [text, setText] = useState("");
  const [toDos, setToDos] = useState({});
  useEffect(() => {
    loadToDos();
  }, []);
  const travel = () => setWorking(false);
  const work = () => setWorking(true);
  const onChangeText = (payload) => setText(payload);
  const saveToDos = async (toSave) => {
    await AsyncStorage.setItem(STORAGE_KEY, JSON.stringify(toSave));
  };
  const loadToDos = async () => {
    const s = await AsyncStorage.getItem(STORAGE_KEY);
    setToDos(JSON.parse(s));
  };

  const addToDo = async () => {
    if (text === "") {
      return;
    }
    const newToDos = {
      ...toDos,
      [Date.now()]: { text, working },
    };
    setToDos(newToDos);
    await saveToDos(newToDos);
    setText("");
  };
  return (
    <View style={styles.container}>
      <StatusBar style="auto" />
      <View style={styles.header}>
        <TouchableOpacity onPress={work}>
          <Text
            style={{ ...styles.btnText, color: working ? "white" : theme.grey }}
          >
            Work
          </Text>
        </TouchableOpacity>
        <TouchableOpacity onPress={travel}>
          <Text
            style={{
              ...styles.btnText,
              color: !working ? "white" : theme.grey,
            }}
          >
            Travel
          </Text>
        </TouchableOpacity>
      </View>
      <TextInput
        onSubmitEditing={addToDo}
        onChangeText={onChangeText}
        returnKeyType="done"
        value={text}
        placeholder={
          working ? "What do you have to do?" : "Where do you want to go?"
        }
        style={styles.input}
      />
      <ScrollView>
        {Object.keys(toDos).map((key) =>
          toDos[key].working === working ? (
            <View style={styles.toDo} key={key}>
              <Text style={styles.toDoText}>{toDos[key].text}</Text>
            </View>
          ) : null
        )}
      </ScrollView>
    </View>
  );
}

在scrollview标记中，我理解如果“toDos[key].working === working”，显示工作的待办事项列表是可以理解的，但如果不是，它不应该什么都不显示吗？我不明白它怎么会显示旅行的待办事项列表，即使我没有采取任何行动
这个代码是我正在听的一个讲座中的现成代码。