The MongoDB forEach operator is a function that takes a JavaScript function as an argument and applies that function to every document in a result set. You can use this function to interact with your MongoDB documents in real time.
Here’s an example of how to use the forEach operator in MongoDB:
1. Connect to your MongoDB instance. Normally, this might be through the `mongo` shell.
2. Select the database you want to use with `use
3. After selecting the database, you’ll use the collection of documents you want to target:
```
db.collection_name.find().forEach(function(document) {
print(“Document ID: “ + document._id)
});
```
In this example, `.find()` is used to get a collection of all documents in `collection_name`. We then use `.forEach()` to apply a function to every document in that collection. In this case, our function is taking each document, and printing the `_id` field.
Remember, in MongoDB, every document has an `_id` field by default, so this should work on any collection.
You can also use the `forEach` function to modify the documents in a collection:
```
db.collection_name.find().forEach(function(document) {
db.collection_name.updateOne(
{ _id: document._id },
{ $set: { “updated”: true } }
)
});
```
In this case, for each document, we’re using the `updateOne` function to set an `updated` field to `true`.
This is a powerful function that allows for large scale read and write operations on a MongoDB collection.
