node.js strange syntax for "delete"

Question

node.js strange syntax for "delete"

what's the delete used for? I didn't see such grammar before, can anybody help me? the code snippet is very easy and it is used the node.js , mongoose , mongodb

function _update(game, callback) {
    if (!game) {
        callback(new Error("Game must be provided."));
        return;
    }
    if (!game.gameId) {
        callback(new Error("Game id should be provided"));
        return;
    }

    var updates = (game instanceof Game) ? game.toObject() : game;
    delete updates._id;
    updates.modifiedDate = new Date();

    Game.findOneAndUpdate({"_id": game.id, "deleted" : {"$ne": true}}, updates, callback);
}

node.js
mongodb
mongoose

Answer 1

delete in JavaScript removes the property from the object.

var game = {
    id: 1
}

console.log(game);  // Object {id: 1}

delete game.id

console.log(game);  // undefined

Answer 2

It is used to remove a property from an object. So in this instance it removes the _id property from updates