huangciyin / mongodb-change-streams-bug-demo

Mongodb change streams Bug demo

Change

This bug has been fixed by mongodb.
Ref to PR: mongodb/node-mongodb-native#1816

Mongodb Change Streams Node.js Example

This is demo project shows mongodb change streams change event bug.

1. listen to change twice:

// listen to change twice
changeStream.on("change", function(change) {
  console.log("change callback1");
});

changeStream.on("change", function(change) {
  console.log("change callback2");
});

2. insert a doc

// insert few data with timeout so that we can watch it happening
setTimeout(function() {
  collection.insertOne({ batman: "bruce wayne" }, function(err) {
    assert.ifError(err);
  });
}, 1000);

3. problem: each change callback was called twice

run node index.js, output:

change callback1
change callback2
change callback1
change callback2

expected behavior:

change callback1
change callback2