嘿，我正在尝试使用 react-native 和 firebase 作为我的主数据库来构建一个博客应用程序

Question

Hey i am trying to build a blog app but i am facing an error in the posting of the blog and i think the error is in the file 'screens/main/Home.js' that says 'Type Error: null is not an object (evaluating quearySnapshot.forEach')'

source code: https://github.com/Sakshamz4554/reactnativeblogapp

Answer 1

The above error is due to quearySnapshot in your code is not an array but null. Before using an array operation to a variable, it's always better to check if its value is not null and have length more than 0 like shown below

function getBlogData() {
      firestore().collection('usersBlog')
      .doc(auth().currentUser.uid)
      .collection('blogs')
      .onSnapshot((quearySnapshot) => {
         const data = []
         quearySnapshot?.length > 0 && quearySnapshot.forEach((documentSnapshot) => {
            data.push({
               ...documentSnapshot.data(),
               id: documentSnapshot.id
            })
         })
         setBlogs(data)
      })
   }