为什么在使用MongoDB的$ push将新对象添加到数组时添加带有ObjectID的_id？

您可以

_id

tournamentSessions

_id

false

var Player = mongoose.model('Player', Schema({    createdAt: { type: Date, default: Date.now },    lastActiveAt: Date,    clientVersion: String,    tournamentSessions: [new Schema({        tournament: { type: Schema.Types.ObjectId, ref: 'Tournament' },        level: Number,        status: String,        score: Number    }, { _id: false })],    friends: Array}));