Quick Mongo Seed

Quick Mongo Seed is an npm module designed to simplify the process of seeding a MongoDB database for your Node.js applications, particularly when writing unit tests using Jest. It allows you to easily populate your MongoDB collections with data from seed files.

Installation

npm i --save-dev quick-mongo-seed

Usage

To use this package, create a folder where you will store your seed data. The seed data will be stored in files whose names follow this format, .seed.js. So if you have a model for users called User, you should create a seed file called user.seed.js that has the seed data for users.

Use the function in your test files as shown below. It will automatically seed the database before tests and close the connection clearing the database after all tests have run.

setUpDb("databaseName",true,"mongodb://127.0.0.1","/path/to/seedFiles")

Below is an example using supertest.

import {app} from '../index.js'
import supertest from 'supertest'
import { setupDB } from "quick-mongo-seed"

const request =supertest(app)
setUpDb("databaseName",true,"mongodb://127.0.0.1","/path/to/seedFiles")
it("should return all products that belong to a particular user", async ()=>{
  
const res= await request.post("/products/list").send({
    email:"[email protected]"
})
expect(res.status).toBe(200)
expect(res.body[0].publisher).toBe("[email protected]")


})

In the example above, we seed our database with products and users from files, product.seed.js and user.seed.js which are located at "/path/to/seedFiles". Parameters:

• databaseName (Type: string): The name of the MongoDB database to be used for seeding.

• runSaveMiddleware (Type: boolean): Determines the seeding method. Set to true for create() and false for insertMany().

• connection_url (Type: string): The connection string to the MongoDB server.

• seedDir (Type: string): The path to the folder containing the seed files.

Seed Files Format

Seed files should follow a specific naming convention and export data in a particular format:

1. File Naming Convention: Seed files should be named in the following format: <model name>.seed.js, where <model name> corresponds to the name of the MongoDB model or collection to which the data should be seeded. For example:

   • If you want to populate the "Users" collection, name the seed file as user.seed.js.
   • For the "Products" collection, use the name product.seed.js.

2. Data Export Format: Each seed file should export data in the following format using the export default syntax:

   export default [
       {
           // Data for the first document
           key1: value1,
           key2: value2,
           // ...
       },
       {
           // Data for the second document
           key1: value1,
           key2: value2,
           // ...
       },
       // Additional documents as needed
   ]

Using the runSaveMiddleware Parameter

The runSaveMiddleware parameter in the setupDB function controls whether to use create() or insertMany() when populating the database. This parameter affects the behavior of schema validations and middleware in your MongoDB models.

• When runSaveMiddleware is set to true:

  • The create() method is used to insert documents into the database.
  • This method invokes schema validations and triggers any associated middleware in your MongoDB models.
  • Schema validations ensure that data adheres to the defined schema, enforcing constraints such as required fields, data types, and more.

• When runSaveMiddleware is set to false:

  • The insertMany() method is used to insert documents into the database.
  • This method does not trigger schema validations or middleware in your MongoDB models.
  • Data is inserted directly into the database without schema checks or custom logic defined in your models.

Example:

Suppose you have a MongoDB model for users defined as follows:

import mongoose from 'mongoose';

const userSchema = new mongoose.Schema({
    email: {
        type: String,
        required: [true, "An email must be provided"],
    },
    password: {
        type: String,
        required: [true, "A password must be provided"],
    },
});

const User = mongoose.model("User", userSchema);

export default User;

If you call setupDB with runSaveMiddleware set to true:

• It will use User.create() to insert data into the "User" collection.
• Schema validations will be enforced, ensuring that data meets the defined schema requirements.

If you call setupDB with runSaveMiddleware set to false:

• It will use User.insertMany() to insert data into the "User" collection.
• Schema validations and middleware will be bypassed, allowing data to be inserted without validation checks.

Choose the appropriate value for runSaveMiddleware based on your testing and seeding needs, considering whether you want schema validations and middleware to be applied during data insertion.

Jest Configuration

This package has been tested using the following Jest configuration file. Include this at the root of your project;

module.exports = {
    preset: 'ts-jest',
    testEnvironment: 'node',
    testTimeout:1000000000,
    transform: {
      '^.+\\.ts?$': 'ts-jest',
    },
    transformIgnorePatterns: ['<rootDir>/node_modules/'],
  };

I'm using ts-jest so if you are working with Typescript, make sure to have that package installed. Also make sure you have "type":"module" in your package.json. If you are using typescript make sure that atleast you have this:

 "compilerOptions": {
    "target": "ES2020",
    "module": "ES2020",
    "outDir": "dist",
    "moduleResolution": "node",
    "esModuleInterop": true,
    "resolveJsonModule": true,
    "strict": true,
    "noImplicitAny": false
  }