我是 React/编程新手,在获取/显示数据时遇到问题。我的代码返回以下错误。提前感谢您的帮助。
类型错误:类型错误:未定义不是对象(评估“data.filter”)
import useFetch from 'react-fetch-hook'
const { data } = useFetch('http://192.168.2.94:3000/list-categories')
const locations = props.navigation.getParam('locationId')
const displayedCategories = data.filter( // ERROR HERE
cat => cat.locId.indexOf(locations) >= 0
)
const renderGridItem = itemData => {
return (
<CategoryGridTile
image={itemData.item.image}
title={itemData.item.title}
/>
)
}
return (
<FlatList
keyExtractor={(item, index) => item.id}
data={displayedCategories}
renderItem={renderGridItem}
/>
)
}
最佳答案
useFetch
返回一个 isLoading
标志以及数据,您必须使用这些数据来显示加载指示器,直到数据可用
const { isLoading, data } = useFetch('http://192.168.2.94:3000/list-categories');
if(isLoading) {
return <span>Loading...</span>
}
const locations = props.navigation.getParam('locationId')
const displayedCategories = data.filter(
cat => cat.locId.indexOf(locations) >= 0
)
const renderGridItem = itemData => {
return (
<CategoryGridTile
image={itemData.item.image}
title={itemData.item.title}
/>
)
}
return (
<FlatList
keyExtractor={(item, index) => item.id}
data={displayedCategories}
renderItem={renderGridItem}
/>
)
关于javascript - 类型错误 : undefined is not an object (evaluating 'data.filter' ) - React Native,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59243309/