schema-dsl
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      • MongoDB exporter documentation

      Overview

      MongoDBExporter Convert the JSON Schema generated by schema-dsl into MongoDB's $jsonSchema validation format, which can be directly used for document validation when creating a collection.

      Core functions

      • ✅ Convert to MongoDB $jsonSchema format
      • ✅ Automatic mapping type is BSON type
      • ✅ Keep all constraints
      • ✅ Generate createCollection command
      • ✅Support strict/loose validation mode

      quick start

      import { s, exporters } from 'schema-dsl/pure';

// 1. Define Schema
const userSchema = s({
  username: 'string:3-32!',
  email: 'email!',
  age: 'number:18-120'
});

// 2. Create exporter
const exporter = new exporters.MongoDBExporter();

// 3. Export to MongoDB Schema
const mongoSchema = exporter.export(userSchema);
console.log(JSON.stringify(mongoSchema, null, 2));

      Output:

      {
  "$jsonSchema": {
    "bsonType": "object",
    "required": ["username", "email"],
    "properties": {
      "username": {
        "bsonType": "string",
        "minLength": 3,
        "maxLength": 32
      },
      "email": {
        "bsonType": "string"
      },
      "age": {
        "bsonType": "double",
        "minimum": 18,
        "maximum": 120
      }
    }
  }
}

      API reference

      Constructor

      new MongoDBExporter(options)

      Parameters:

      Parametertypedefault valueDescription
      options.strictbooleanfalseWhether to use strict validation mode

      method

      export(jsonSchema)

      Convert JSON Schema to MongoDB Validation Schema.

      const mongoSchema = exporter.export(jsonSchema);

      Parameters:

      • jsonSchema (Object): JSON Schema object generated by schema-dsl

      Return Value:

      • Object: MongoDB authentication object containing $jsonSchema

      generateCreateCommand(collectionName, jsonSchema)

      Generate createCollection command object.

      const command = exporter.generateCreateCommand('users', userSchema);

      Parameters:

      • collectionName (string): collection name
      • jsonSchema (Object): JSON Schema object

      Return Value:

      {
  collectionName: 'users',
  options: {
    validator: { $jsonSchema: {...} },
    validationLevel: 'moderate', // or 'strict'
    validationAction: 'error'
  }
}

      generateCommand(collectionName, jsonSchema)

      Generate an executable MongoDB command string.

      const commandStr = exporter.generateCommand('users', userSchema);
console.log(commandStr);

      Output:

      db.createCollection("users", {
  "validator": {
    "$jsonSchema": {
      "bsonType": "object",
      ...
    }
  },
  "validationLevel": "moderate",
  "validationAction": "error"
})

      MongoDBExporter.export(jsonSchema) (static method)

      Fast export without instantiation.

      const mongoSchema = exporters.MongoDBExporter.export(userSchema);

      Configuration options

      Authentication mode

      modelDescription
      strict: false (default)validationLevel: 'moderate' - ​​Validates only fields involved in insert and update operations
      strict: truevalidationLevel: 'strict' - ​​Validates all insert and update operations
      // strict mode
const strictExporter = new exporters.MongoDBExporter({ strict: true });

      Complete example

      User set validation

      import { s, exporters } from 'schema-dsl/pure';

//Define complex user Schema
const userSchema = s({
  _id: 'string!',
  username: s('string:3-32!').pattern(/^[a-zA-Z0-9_]+$/)
    .label('username'),
  email: s('email!').label('mailbox'),
  profile: {
    bio: 'string:500',
    avatar: 'url'
  },
  status: 'active|inactive|banned',
  createdAt: 'datetime!'
});

// Export and generate commands
const exporter = new exporters.MongoDBExporter({ strict: true });
const command = exporter.generateCommand('users', userSchema);

console.log(command);

      Used in MongoDB

      import { MongoClient } from 'mongodb';

async function createValidatedCollection() {
  const client = new MongoClient('mongodb://localhost:27017');
  await client.connect();

  const db = client.db('myapp');

  // Get validation Schema
  const exporter = new exporters.MongoDBExporter({ strict: true });
  const { options } = exporter.generateCreateCommand('users', userSchema);

  //Create a collection with validation
  await db.createCollection('users', options);

  console.log('Collection created successfully, document validation enabled');
}

      type mapping

      JSON Schema typeMongoDB BSON type
      stringstring
      numberdouble
      integerint
      booleanbool
      objectobject
      arrayarray
      nullnull

      constraint mapping

      JSON Schema constraintsMongoDB constraints
      minLengthminLength
      maxLengthmaxLength
      minimumminimum
      maximummaximum
      patternpattern
      enumenum
      minItemsminItems
      maxItemsmaxItems

      Export restrictions

      ⚠️ IMPORTANT: Not all schema-dsl features can be exported to a database schema.

      Exported features not supported:

      • ❌ Conditional validation logic (s.match(), s.if())
      • ❌ Custom validator (.custom())
      • ❌ Complex JSON Schema keywords (allOf, anyOf, oneOf)
      • ❌ Custom error message (.messages())

      Detailed instructions: Please read Export restrictions document

      Corresponding sample file

      Example entry: mongodb-exporter.ts Description: Covers $jsonSchema export, generateCreateCommand() and generateCommand(), corresponding to the validation set creation scenario in the document.