Modifiers

Mongo-Style Modifiers

A modifier is an object that describes how to update a document in place by changing some of its fields. Some examples:

// Set the 'admin' property on the document to true
{$set: {admin: true}}

// Add 2 to the 'votes' property, and add "Traz"
// to the end of the 'supporters' array
{$inc: {votes: 2}, $push: {supporters: "Traz"}}

But if a modifier doesn't contain any $-operators, then it is instead interpreted as a literal document, and completely replaces whatever was previously in the database. (Literal document modifiers are not currently supported by validated updates.)

// Find the document with id "123", and completely replace it.
Users.update({_id: "123"}, {name: "Alice", friends: ["Bob"]});

See the full list of modifiers.