A TypeScript package that generates Nest.js/Mongoose schemas from existing MongoDB collections.

npm install mongo-to-mongoose-schema

import { generateMongooseSchemas } from 'mongo-to-mongoose-schema';

generateMongooseSchemas('mongodb://localhost/your-database', './schemas');

This will generate TypeScript schema files for all non-empty collections in the your-database database and place them in the ./schemas directory.

1. The package connects to the provided MongoDB database URI.
2. It retrieves a list of all collections, excluding system collections.
3. For each non-empty collection:
   • It fetches a sample document from the collection.
   • It infers the schema structure based on the sample document's properties and data types.
   • It generates a TypeScript schema file for the Nest.js/Mongoose model, using the inferred schema structure.

The generated schema file will have the following structure:

import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
import { Document, Types } from 'mongoose';

@Schema({ collection: 'your_collection_name' })
export class YourCollectionName extends Document {
  @Prop()
  stringProperty: string;

  @Prop()
  numberProperty: number;

  @Prop()
  booleanProperty: boolean;

  @Prop()
  dateProperty: Date;

  @Prop()
  objectIdProperty: Types.ObjectId;

  @Prop()
  arrayProperty: [{ nestedProperty: string }];

  @Prop()
  nestedObjectProperty: { nestedProperty: string };

  // ... other properties
}

export const YourCollectionNameSchema = SchemaFactory.createForClass(YourCollectionName);

The package infers the appropriate types for properties based on the sample document's data. It supports common types like string, number, boolean, Date, Types.ObjectId, arrays, and nested objects up to a maximum depth of 5 levels.

You can then import and use the generated schema in your Nest.js application.

The generateMongooseSchemas function accepts two arguments:

1. databaseUri (string): The MongoDB connection URI.
2. outputDir (string): The output directory where the schema files will be generated.

• The package generates schemas based on a single sample document from each collection. If the documents in a collection have varying structures, the generated schema may not accurately represent all possible data shapes.
• Nested objects and arrays are supported up to a maximum depth of 5 levels to avoid potential circular references. This depth can be adjusted in the utils.ts file by modifying the MAX_DEPTH constant.

Contributions are welcome! Please feel free to open issues or submit pull requests on the GitHub repository.

This project is licensed under the MIT License.