Docs Menu

Docs Home → Develop Applications → Atlas Device SDKs

CRUD - Update - Node.js SDK

On this page

  • Update an Object
  • Upsert an Object
  • Bulk Update a Collection

Update an Object

You can add, modify, or delete properties of a Realm object inside of a write transaction in the same way that you would update any other JavaScript object.

// Open a transaction.
realm.write(() => {
  // Get a dog to update.
  const dog = realm.objects("Dog")[0];
  // Update some properties on the instance.
  // These changes are saved to the realm.
  dog.name = "Maximilian";
  dog.age += 1;
});

Tip

Update Related and Embedded Objects

To update a property of an embedded object or a related object, modify the property with dot-notation or bracket-notation as if it were in a regular, nested object.

Upsert an Object

To upsert an object, call Realm.create() with the update mode set to modified. The operation either inserts a new object with the given primary key or updates an existing object that already has that primary key.

realm.write(() => {
  // Add a new person to the realm. Since nobody with ID 1234
  // has been added yet, this adds the instance to the realm.
  person = realm.create(
    "Person",
    { _id: 1234, name: "Joe", age: 40 },
    "modified"
  );
  // If an object exists, setting the third parameter (`updateMode`) to
  // "modified" only updates properties that have changed, resulting in
  // faster operations.
  person = realm.create(
    "Person",
    { _id: 1234, name: "Joseph", age: 40 },
    "modified"
  );
});

Bulk Update a Collection

To apply an update to a collection of objects, iterate through the collection (e.g. with for...of). In the loop, update each object individually:

realm.write(() => {
  // Create someone to take care of some dogs.
  const person = realm.create("Person", { name: "Ali" });
  // Find dogs younger than 2.
  const puppies = realm.objects("Dog").filtered("age < 2");
  // Loop through to update.
  for (const puppy of puppies) {
    // Give all puppies to Ali.
    puppy.owner = person;
  }
});

Note

Inverse Relationships

Thanks to an inverse relationship from Dog.owner to Person.dogs, Realm automatically updates Ali's list of dogs whenever we set her as a puppy's owner.

← CRUD - Read - Node.js SDK
CRUD - Delete - Node.js SDK →

On this page