作用：保证保存文档时，可以按照Schema设置的字段进行设置，即文档限制只能在 Schema上 。

1.1【required】：数据必填

  1. //将name设置为必填字段，如果没有name字段，文档将不被保存，且出现错误提示
  2. const mongoose = require('mongoose')
  3. mongoose.connect('mongodb://localhost:27017/student')
  4. var Schema =new mongoose.Schema({
  5.   name:{
  6.     type:String,
  7.     required:true
  8.   },
  9.   age:Number
  10. })
  11. var stuModel = mongoose.model('students', Schema);
  12. new stuModel({age:20}).save((err,doc)=>{
  13.   if(err){
  14.     return console.log(err)
  15.   }
  16.   console.log(doc)
  17. })
  19. //报错：name: Path `name` is required.

1.2【default】：默认值

  1. //设置age字段的默认值为18，如果不设置age字段，则会取默认值
  2. const mongoose = require('mongoose')
  3. mongoose.connect('mongodb://localhost:27017/student')
  4. var Schema =new mongoose.Schema({
  5.   name:String,
  6.   age:{
  7.     type:Number,
  8.     default:18
  9.   }
  10. })
  11. var stuModel = mongoose.model('students', Schema);
  12. new stuModel({name:'李雷'}).save((err,doc)=>{
  13.   if(err){
  14.     return console.log(err)
  15.   }
  16.   console.log(doc)
  17. })
  19. //{ age: 18, _id: 6018f3bd7e51343e6c4f212b, name: '李雷', __v: 0 }

1.3【min】【max】：最小/大值

  • 只适用于数字 ```javascript //将age的取值范围设置为[0,10]。如果age取值为20，文档将不被保存，且出现错误提示 const mongoose = require(‘mongoose’) mongoose.connect(‘mongodb://localhost:27017/student’) var Schema =new mongoose.Schema({ name:String, age:{ type:Number, min:10, max:18 } }) var stuModel = mongoose.model(‘students’, Schema); new stuModel({name:’李雷’,age:20}).save((err,doc)=>{ if(err){ return console.log(err) } console.log(doc) })

//age: Path age (20) is more than maximum allowed value (18).

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  3. ### 1.4【match】：正则匹配
  5. - 只适用于字符串
  6. ```javascript
  7. //将name的match设置为必须存在'01'字符。如果name不存在'01'，文档将不被保存，且出现错误提示
  8. const mongoose = require('mongoose')
  9. mongoose.connect('mongodb://localhost:27017/student')
  10. var Schema =new mongoose.Schema({
  11.   name:{type:String,match:/01/},
  12.   age:Number,
  13. })
  14. var stuModel = mongoose.model('students', Schema);
  15. new stuModel({name:'李雷',age:20}).save((err,doc)=>{
  16.   if(err){
  17.     return console.log(err)
  18.   }
  19.   console.log(doc)
  20. })
  22. //name: Path `name` is invalid (李雷).

1.5【enum】：枚举匹配

  • 只适用于字符串 ```javascript //将name的枚举取值设置为[‘zs’,’ls’,’ww’]，如果name不在枚举范围内取值，文档将不被保存，且出现错误提示 const mongoose = require(‘mongoose’) mongoose.connect(‘mongodb://localhost:27017/student’) var Schema =new mongoose.Schema({ name:{type:String,enum:[‘zs’,’ls’,’ww’]}, age:Number, }) var stuModel = mongoose.model(‘students’, Schema); new stuModel({name:’lss’,age:20}).save((err,doc)=>{ if(err){ return console.log(err) } console.log(doc) })

//name: ValidatorError: lss is not a valid enum value for path name.

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  3. ### 1.6【validate】：自定义匹配
  5. - `validate`实际上是一个函数，函数的参数代表当前字段，返回`true`表示通过验证，返回`false`表示未通过验证。
  6. ```javascript
  7. //定义名字name的长度必须在4个字符以上
  8. const mongoose = require('mongoose')
  9. mongoose.connect('mongodb://localhost:27017/student')
  10. var Schema =new mongoose.Schema({
  11.   name:{type:String,validate:nameLength},
  12.   age:Number,
  13. })
  14. var stuModel = mongoose.model('students', Schema);
  15. new stuModel({name:'abcd',age:20}).save((err,doc)=>{
  16.   if(err){
  17.     return console.log(err)
  18.   }
  19.   console.log(doc)
  20. })
  22. function nameLength(arg){
  23.   if(arg.length>4){
  24.     return true
  25.   }
  26.   return false
  27. }
  29. //name: Validator failed for path `name` with value `abcd`