README.md

@shujau/mockingjs

A flexible and powerful mock data generator built on top of Faker.js, designed to streamline the creation of realistic test data for your JavaScript applications.

Features

• 🔧 Flexible schema definition
• 🏗 Support for nested objects and arrays
• 🎭 Custom generator functions
• 🌈 Wide range of built-in data types
• 🔢 Consistent data generation with seeding
• 🧩 Custom type definitions
• 🔍 Automatic schema inference from sample data
• ⚙️ Backwards compatibility with previous API

Installation

Using npm:

npm install @shujau/mockingjs

Using yarn:

yarn add @shujau/mockingjs

Quick Start

import factory from '@shujau/mockingjs';

const users = factory({
  id: 'uniqueInt',
  name: 'fullName',
  email: 'email',
  age: { type: 'number', options: { min: 18, max: 65 } }
}, { quantity: 2 });

console.log(users);

Usage Tips

Obtaining a Single Object

The factory function always returns an array, even when generating a single item. If you need a single object, you can easily extract it using array destructuring or indexing:

// Using array destructuring
const [user] = factory({ name: 'fullName', email: 'email' });

// Or using array indexing
const user = factory({ name: 'fullName', email: 'email' })[0];

This design ensures consistency and flexibility in the API, allowing you to always work with the result in the same way, regardless of the quantity generated.

API Reference

factory(schemaOrSample, options)

Generates mock data based on the provided schema or sample.

• schemaOrSample: Object or Array defining the structure of the data to generate, or a sample object to infer the schema from.
• options: Object (optional)
  • quantity: Number of objects to generate (default: 1)
  • seed: Seed for consistent random generation
  • isSample: Boolean indicating if the first argument is a sample object (default: false)
  • cache: Object for caching generator functions (advanced usage)

Returns an array of generated objects.

Defining Schemas

Simple Array

const schema = ['id', 'name', 'email'];
const users = factory(schema, { quantity: 2 });

This above schema will generate objects with 'id', 'name', and 'email' properties, each using the default generator for its field name. Note that the isSample option should not be used when using an array as the schema.

Object with Types

const schema = {
  id: 'uuid',
  name: 'fullName',
  email: 'email'
};

Complex Object

const schema = {
  id: 'uniqueInt',
  name: 'fullName',
  email: 'email',
  age: { type: 'number', options: { min: 18, max: 65 } },
  address: {
    type: {
      street: 'street',
      city: 'city',
      country: 'country'
    }
  },
  tags: { type: ['word'], length: 3 }
};

Supported Types

• Basic: string, number, boolean, uuid
• Person: firstName, lastName, fullName, gender, age
• Contact: email, phone, mobile
• Internet: username, password, url, avatar
• Address: address, street, city, state, country, zipCode, latitude, longitude
• Company: company, companySuffix, jobTitle
• Finance: creditCard, creditCardCVV, iban, bic, bitcoinAddress
• Content: paragraph, sentence, word, description
• Date/Time: date, datetime, past, future, recent, month, weekday
• Identifiers: uniqueInt
• Miscellaneous: color

Advanced Usage

Seeding for Consistent Data

You can set a seed to generate consistent data across multiple runs. This can be done in two ways:

1. Using the setSeed function:

import { factory, setSeed } from '@shujau/mockingjs';

setSeed(123);
const users = factory({ name: 'fullName', email: 'email' }, { quantity: 2 });

2. Using the seed option in the factory function (recommended):

import { factory } from '@shujau/mockingjs';

const users = factory(
  { name: 'fullName', email: 'email' },
  { quantity: 2, seed: 123 }
);

// This will generate the same data as the previous example

Using the seed option is recommended as it allows for more localized control over seeding, especially when you need different seeds for different factory calls in the same script.

Custom Type Definitions

import { factory, defineType } from '@shujau/mockingjs';

defineType('customEmail', () => `user_${Math.random().toString(36).substr(2, 5)}@example.com`);

const users = factory({
  id: 'uniqueInt',
  email: 'customEmail'
}, { quantity: 2 });

Schema Inference from Sample Data

import { factory } from '@shujau/mockingjs';

const sampleUser = {
  id: 1,
  name: "John Doe",
  email: "[email protected]",
  age: 30
};

const users = factory(sampleUser, { quantity: 3, isSample: true });

Unique Integer Management

import { factory, setUniqueIntStart, resetUniqueIntCounter } from '@shujau/mockingjs';

setUniqueIntStart(1000);
const users = factory({ id: 'uniqueInt', name: 'fullName' }, { quantity: 2 });

resetUniqueIntCounter(); // Resets the counter to 0

Migrating from v1.x to v2.0

Version 2.0 introduces a new options object for the factory function, but maintains backwards compatibility:

// Old way (still supported)
const oldWay = factory(schema, 2);

// New way
const newWay = factory(schema, { quantity: 2 });

// Using sample data (previously factoryFromSample)
const fromSample = factory(sampleData, { quantity: 2, isSample: true });

The factoryFromSample function is deprecated and will be removed in the next major version.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.