Generates fixtures for mongoose. Simply provide the schema or model, and it will generate mock data based on the types and constraints of the schema.

• Installation
• Usage
• Accurate data generation
• Options
• Resolving paths
• Overriding values
• Schema rules

npm i -D @mocking-bird/mongoose

import { Schema } from 'mongoose';
import { MongooseFixture } from '@mocking-bird/mongoose';

const schema = new Schema({
  name: String,
  email: String,
  age: { type: Number, min: 18, max: 100 },
  workEmail: String,
  address: {
    street: String,
    city: String,
    country: String,
  },
  createdAt: Date,
  updatedAt: Date,
});

const fixture = new MongooseFixture(schema);

const data = fixture.generate();

Example output:

{
  "name": "Turner, Thompson and Mueller",
  "email": "Jerome.Mraz58@yahoo.com",
  "age": 55,
  "workEmail": "Sabrina99@hotmail.com",
  "address": {
    "street": "Apt. 123 1234",
    "city": "Lake Ethylburgh",
    "country": "Gambia"
  },
  "createdAt": "2023-09-11T05:38:59.576Z",
  "updatedAt": "2024-02-26T08:25:16.412Z",
  "_id": "a84f58e2fcff9dfaf148d7bf"
}

const data = fixture.bulkGenerate(1000);

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Generated data are not only random-random but also contextually accurate based on field names and types. It leverages the fuzzy search, or formally, approximate string search algorithm to search for the suitable faker to generate realistic data that relate to the field.

For example:

• workEmail -> Jerome.Mraz58@yahoo.com
• employeePhoneNumber -> 550-459-6013
• uploadedFileName -> file-1234.pdf

Of course, there are still some limitations when it comes to complex field names with multiple parts, in which case the default fakers are applied. The default fakers are fallbacks in case the fuzzy search score is not high enough. The default fakers may return, depending on the field type, a random string, number, or date, and so on.

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FieldPath is a string that represents the path of a field in the schema. It can be a nested path, such as address.street. It can also be a wildcard path, such as address.*, which means all fields under address.

fixture.generate(
  {},
  {
    exclude: ['createdAt', 'updatedAt'],
    isAccurate: false,
    requiredOnly: true,
    rules: [
      {
        path: 'address.city',
        enum: ['Berlin', 'Frankfurt'],
      },
      {
        path: 'age',
        min: 18,
        max: 60,
      },
      {
        path: 'workEmail',
        pattern: /@gmail.com$/,
      },
    ],
  },
);

You can also set global options for all fixtures:

MongooseFixture.setGlobalOptions({
  isAccurate: false,
  requiredOnly: true,
});

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When working with nested data structures, you may want to resolve the paths to the fields. This is especially useful when you want to exclude or apply rules to fields that are nested.

fixture.generate({}, { exclude: ['address.city'] });

You can also use wildcard paths to exclude or apply rules to all fields under a certain path:

fixture.generate({}, { exclude: ['address.*'] });

fixture.generate({
  'person.*.jobTitle': 'Software Engineer',
});

fixture.generate({
  'person.**.is*': true,
}); // will override every field that starts with `is` to true, e.g., isDefault, isCool etc...

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You can override the generated values by providing a map of values to override:

fixture.generate({
  name: 'John Doe',
  email: 'test@example.com',
  age: 25,
});

// or using wildcards

fixture.generate({
  'address.**.buildingNo': '1234',
});

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The generated values comply with the schema rules, for example:

const schema = new Schema({
  name: { type: String, required: true },
  age: { type: Number, min: 18, max: 100 },
  city: { type: String, enum: ['Berlin', 'Frankfurt'] },
});

In this case, the age will be a number between 18 and 100, and the city will be either Berlin or Frankfurt.

Limitation

There is a limitation when it comes to custom schema validators. In the below example, the generated value cannot comply with the custom validator, as it's a function.

const schema = new Schema({
  name: {
    type: String,
    validate: {
      validator: (v) => v.length > 5,
      message: 'Name must be longer than 5 characters',
    },
  },
});

Alternatively, you can define the same schema validator as a custom rule:

fixture.generate(schema, {
  rules: [
    {
      path: 'name',
      min: 6,
    },
  ],
});