错误类型:TypeError:未定义的不是函数。为什么我的对象不能转换为数组?

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英文:

ERROR TypeError: undefined is not a function Why my object is not converting to array?

问题

ERROR TypeError: undefined is not a function 为什么我的对象无法转换为数组?这是我面临的错误,我试图映射当前为对象的所有项目,但我想将它们转换为数组以进行映射,我该如何做到这一点?它尚未转换为数组,我尝试了一些互联网上的解决方案,我该如何做到这一点?

Currenlty其给我null,当我首次使用const propertyValues = Object.values(item);时,它给我了ERROR TypeError:undefined is not a function错误

const renderImages = ({ item, index }) => {
console.log(item)
if (!item || !Array.isArray(item)) {
return null;
}

const propertyValues = Object.values(item);
console.log(propertyValues);

return (
<View style={styles.images}>
{item.map((url) => (
<Image key={url} style={styles.pic} source={{ uri: url }} />
))}
</View>
);
};

如果我什么都不做,只是记录item,它会记录类似这样的东西:

LOG {"picture": "https://firebasestorage.googleapis.com/v0/b/myprojectfirebase.appspot.com/o/file%3A%2Fdata%2Fuser%2F0%2Fhost.exp.exponent%2Fcache%2FExperienceData%2F%252540anonymous%25252FYounme-4dc528f7-0647-403c-9671-6a595b71bf0b%2FImagePicker%2Fba5eb500-c4e3-4199-9cef-5a8bfb3b1219.jpeg?alt=media&token=49041038-deef-40d9-9809-41210982ae36"}

{
userdata ?
<FlashList
data={userdata.pictures}
renderItem={renderImages}
keyExtractor={(item, index) => index.toString()}
getItemCount={() => userdata.pictures.length}
getItem={(data, index) => data[index]}
initialNumToRender={5}
windowSize={5}
ListHeaderComponent={
...//
}
}
/>

英文:

ERROR TypeError: undefined is not a function Why my object is not converting to array? this is the error that I am facing I am trying to map all the item which is currently object but I want to convert it to array to map all them how can I do that? its not been converted into array I tried some solutions on internet how can I do that?

Currenlty its giving me null and when i first const propertyValues = Object.values(item); it gave me ERROR TypeError: undefined is not a function error

const renderImages = ({ item, index }) =&gt; {
        console.log(item)
        if (!item || !Array.isArray(item)) {
            return null;
        }
        
        const propertyValues = Object.values(item);
        console.log(propertyValues);
        
        return (
            &lt;View style={styles.images}&gt;
                {item.map((url) =&gt; (
                    &lt;Image key={url} style={styles.pic} source={{ uri: url }} /&gt;
                ))}
            &lt;/View&gt;
        );
    };

If i do nothing just log the item it logs something like this:

 LOG  {&quot;picture&quot;: &quot;https://firebasestorage.googleapis.com/v0/b/myprojectfirebase.appspot.com/o/file%3A%2Fdata%2Fuser%2F0%2Fhost.exp.exponent%2Fcache%2FExperienceData%2F%252540anonymous%25252FYounme-4dc528f7-0647-403c-9671-6a595b71bf0b%2FImagePicker%2Fba5eb500-c4e3-4199-9cef-5a8bfb3b1219.jpeg?alt=media&amp;token=49041038-deef-40d9-9809-41210982ae36&quot;}



       {
                    userdata ?
                        &lt;FlashList
                            data={userdata.pictures}
                            renderItem={renderImages}
                            keyExtractor={(item, index) =&gt; index.toString()}
                            getItemCount={() =&gt; userdata.pictures.length}
                            getItem={(data, index) =&gt; data[index]}
                            initialNumToRender={5}
                            windowSize={5}
                            ListHeaderComponent={
                                   ...//
    
    }

}
    
    /&gt;

答案1

得分: 1

如果item是一个对象,此代码将始终返回null

if (!item || !Array.isArray(item)) {
  return null;
}

此外,如果你想创建一个URL数组,你可以简单地使用Object.keys.map来创建一个item URL 数组。

const properties = Object.keys(item);
const values = properties.map((p) => item[p].url);

由于item只有一个picture,为什么不简化:

const renderImages = ({ item, index }) => {
  return (
    <View style={styles.images}>
      <Image key={item.picture} style={styles.pic} source={{ uri: item.picture }} />
    </View>
  );
};
英文:

If item is an object, this code will always return null:

if (!item || !Array.isArray(item)) {
  return null;
}

Additionally, if you want to create an array of URLs, you can simply use Object.keys and .map to create an array of item urls.

const properties = Object.keys(item);
const values = properties.map((p) =&gt; item

.url);

Since item just has one picture, why not simplify:

const renderImages = ({ item, index }) =&gt; {
  return (
    &lt;View style={styles.images}&gt;
      &lt;Image key={item.picture} style={styles.pic} source={{ uri: item.picture }} /&gt;
    &lt;/View&gt;
  );
};

答案2

得分: 1

考虑执行

const renderImages = ({ item, index }) => {
  return (
    <View style={styles.images}>
      <Image key={url.picture} style={styles.pic} source={{ uri: url.picture }} />
    </View>
  );
};
英文:

Consider doing:

const renderImages = ({ item, index }) =&gt; {
  return (
    &lt;View style={styles.images}&gt;
      &lt;Image key={url.picture} style={styles.pic} source={{ uri: url.picture }} /&gt;
    &lt;/View&gt;
  );
};

huangapple
  • 本文由 发表于 2023年2月18日 23:30:36
  • 转载请务必保留本文链接:https://go.coder-hub.com/75494376.html
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