如何在Mongoose模式中设置数组大小的限制 [英] How to set limit for array size in Mongoose schema

问题描述

请告诉我在创建Mongoose模式时是否有任何方法可以设置数组大小的限制.例如

Would you be kind to tell me is there any way to set limitation on array size while creating Mongoose schema. For example

 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'
    }]
})

推荐答案

只需对架构设置进行一些细微调整，就可以添加

With a small tweak to your schema setup you can add a validate option:

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;
}

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