Firestore：如何更新有效负载文档中的特定字段？

Question

How do I access and update a specific field in angular firebase but My Data In payload I have put the image link that easy for u:

Enter This Link and see the Image what I am saying that

 UserVerification(id, _value: number) {


      
     console.log(id,"KKKKK",_value)
    //return this.firestore.collection("DevicesData").doc(id).update({Impact:"100 "}); 
      return this.firestore
     .collection("DevicesData")
     .doc('/' + '00HcetBoNFIOmwEWZ6fo')
    //  .doc(id)
     .update({Impact:"_value"})
     .then(() => {
       console.log('done');
     })
     .catch(function(error) {
      console.error('Error writing document: ', error);
     });
    }

if I use this code then update the data outside the payload but I want to update the data inside the payload?

Answer 1

Your code yes will update the data outside payload, because you didn't specify that. The right way to update a field inside an object in a document (called nested objects):

return this.firestore
           .collection("DevicesData")
           .doc('00HcetBoNFIOmwEWZ6fo')
           .update({'payload.Impact':_value});

You can find the whole documentation here: https://firebase.google.com/docs/firestore/manage-data/add-data#update_fields_in_nested_objects

But this won't work for you , because your payload type is not a map (Object) and that is obvious from the double quote, which mean its a string(make sure when you set it in the right way).
However, if you still want it this way, then you have to update the whole payload string, including other values(also you could do this if the payload is an object, like before):

return this.firestore
           .collection("DevicesData")
           .doc('00HcetBoNFIOmwEWZ6fo')
           .update({payload:{Topic:'IMPACT', MAC:'...', ..., Impact:_value});