请告诉我，在创建Mongoose模式时，有没有办法限制数组大小.例如
var peopleSchema = new Schema({
name: {
type: String,
required: true,
default: true
},
/* here I want to have limit: no more than 10 friends.
Is it possible to define in schema?*/
friends: [{
type: Schema.Types.ObjectId,
ref: 'peopleModel'
}]
})
对模式设置稍加调整，即可添加validate选项:
var peopleSchema = new Schema({
name: {
type: String,
required: true,
default: true
},
friends: {
type: [{
type: Schema.Types.ObjectId,
ref: 'peopleModel'
}],
validate: [arrayLimit, '{PATH} exceeds the limit of 10']
}
});
function arrayLimit(val) {
return val.length <= 10;
}