检查范围之外的变量

Question

在我的代码中，我想有条件地执行查询，然后在模板中检查其加载变量，但前提是执行了查询并且不想在我的文件中出现任何 TypeScript 错误。如何检查此变量在其上下文中可能存在或可能不存在？

我正在使用 Apollo GraphQL。

if( executeMyQuery )
{
    const {
        data, loading: loadingQuery
    } = useQuery( MyQuery );
}

return (
    <View>
        { /* ... some code ... */ }
        { executeMyQuery && loadingQuery ?
            <Text>Query is loading...</Text>
            { /* ... some code ... */ }
        : null }
    </View>
);

打字稿说：Cannot find name 'loadingQuery'.

Answer 1

看看dependent queries

const {
     data, loading: loadingQuery
} = useQuery( MyQuery,    {
 // The query will not execute until the userId exists
 enabled: executeMyQuery,
   }
);

return (
    <View>
        { /* ... some code ... */ }
        { executeMyQuery && loadingQuery ?
            <Text>Query is loading...</Text>
            { /* ... some code ... */ }
        : null }
    </View>
);

Answer 2

通过更改

使用 skip 参数修复了它

if( executeMyQuery )
{
    const {
        data, loading: loadingQuery
    } = useQuery( MyQuery );
}

到

const {
    data, loading: loadingQuery
} = useQuery( MyQuery, {
    skip: executeMyQuery,
} );

检查范围之外的变量

Checking variable outside of its scope

javascript

android

typescript

apollo

react-native