MongoDB: Update property of subarray just updates the first element - node.js

Question

The matching element looks like that:
{
"_id": {
"$oid": "519ebd1cef1fce06f90e3157"
},
"from": "Tester2",
"to": "Tester",
"messages": [
{
"username": "Tester2",
"message": "heeey",
"read": false
},
{
"username": "Tester",
"message": "hi!",
"read": false
},
{
"username": "Tester2",
"message": "test",
"read": false
}
],
}
Now I try to set the read property to the current date just of the subelements where the username is not equal to Tester:
var messages = db.collection('messages');
messages.update(
{
_id: new BSON.ObjectID("519ebd1cef1fce06f90e3157"),
messages: {
$elemMatch: { username: { $ne: "Tester" } }
}
},
{ $set: { 'messages.$.read': new Date() } },
{ multi: true }, function(error, result) {
console.log(error);
console.log(result);
});
But just the first messages subelement read property updates:
{
"_id": {
"$oid": "519ebd1cef1fce06f90e3157"
},
"from": "Tester2",
"to": "Tester",
"messages": [
{
"username": "Tester2",
"message": "heeey",
"read": {
"$date": "2013-01-01T00:00:00.000Z"
}
},
{
"username": "Tester",
"message": "hi!",
"read": false
},
{
"username": "Tester2",
"message": "test",
"read": false
}
],
}
What's wrong with the code?
I'm using node.js v0.10.8 and MongoDB v2.4.3 together with node-mongodb-native.

Answer 1

There's nothing wrong with your code; the $ operator contains the index of the first matching array element. The {multi: true} option only makes the update apply to multiple documents, not array elements. To update multiple array elements in a single update you must specify them by numeric index.
So you'd have to do something like this:
messages.update(
{
_id: new BSON.ObjectID("519ebd1cef1fce06f90e3157")
},
{ $set: {
'messages.0.read': new Date(),
'messages.2.read': new Date()
} },
function (err, result) { ... }
);

Answer 2

This is similar to question: How to Update Multiple Array Elements in mongodb
var set = {}, i, l;
for(i=0,l=messages.length;i<l;i++) {
if(messages[i].username != 'tester') {
set['messages.' + i + '.read'] = new Date();
}
}
.update(objId, {$set:set});

Answer 3

I think ArrayFilters can be used in this case

Answer 4

I know it's a little bit late to answer this question but if you use the $[] operator, it will do the trick.
more details here
https://www.mongodb.com/docs/manual/reference/operator/update/positional-all/
I was able to use it inside an updateMany operation, but it should work also for update
var messages = db.collection('messages');
messages.update(
{
_id: new BSON.ObjectID("519ebd1cef1fce06f90e3157"),
messages: {
$elemMatch: { username: { $ne: "Tester" } }
}
},
{ $set: { 'messages.$[].read': new Date() } },
{ multi: true }, function(error, result) {
console.log(error);
console.log(result);
});