无法删除Firestore查询：AngularFirestoreCollection类型的get不存在

Question

按照以下示例： How to delete document from firestore using where clause

我正在尝试删除Firestore查询，但出现以下错误：

“类型'AngularFirestoreCollection'中不存在属性'get'

var delete_query = this.afs.collection('members', ref => ref.where('name','==','john'));
delete_query.get().then(function(querySnapshot) {
querySnapshot.forEach(function(doc) {
doc.ref.delete();
});});