Mockmagic NPM | npm.io

MockMagic

Introduction

MockMagic is designed to instantly generate mock data from any object schema for testing and development purposes. It's extremely simple and only requires an object schema to generate mock data.

Quick Start

const mockData = generate(schema); // Pass in any object schema to generate mock data
/** 
 * Returns mock data based on the schema
 * { id: 1, name: 'John Doe', email: 'john.doe@example.com', phone: '123-456-7890' }
 */

When should I use this?

Use MockMagic when you need to quickly generate realistic mock data in bulk. It's particularly effective for populating data for different types of data schemas or databases without having to manually assign data types.

How It Works

Compared to most other mock libraries, MockMagic prioritizes key-based data generation rather than data type-based generation. This means that virtually no configuration or setup is required to generate mock data, and you can use it on any object schema.

You can generate mock data instantly on plain objects, objects of objects, Zod schemas, DrizzleOrm schemas, and more.

It recognizes and generates data for common key names (e.g., id, first_name, phone_number, profile_image) in any naming convention—camelCase, snake_case, PascalCase, etc.

If a key isn't recognized, MockMagic defaults to generating data based on the data type specified in the schema.

The library includes a test suite that covers: regular objects, @Zod schemas, and @DrizzleOrm schemas .

Features

Generate mock data based on any object schema.
Map custom keys with data groups.
Easily override default data generation for specific keys or data types.
Supports skipping keys to return null values.
Instantly generate modal for tools like Zod, DrizzleOrm, etc.

Installation

Install MockMagic via npm:

npm i mockmagic

Import

import { generate } from "mockmagic";

Simple Usage

All you need to do to generate mock data is to pass an object schema to the generate function.

const schema = { // Any object schema can be provided. (Plain object, object of objects, zod schemas, driizzle orm schemas, graphql schemas, etc)
  id: '',
  name: '',
  email: '',
  phone: '',
};

const mockData = generate(schema); // Pass in any object schema to generate mock data
/** 
 * { id: 1, name: 'John Doe', email: 'john.doe@example.com', phone: '123-456-7890' }
 */

Usage with other schemas

Using a Zod schema:

import { z } from 'zod';

const schema = z.object({
  id: z.number(),
  name: z.string(),
  email: z.string().email(),
  phone: z.string().min(10).max(12),
});

const mockData = generate(schema.shape);
/** 
 * { id: 1, name: 'John Doe', email: 'john.doe@example.com', phone: '123-456-7890' }
 */

Using a DrizzleOrm schema:

const schema = pgTable("users", {
  id: serial("id").primaryKey().notNull(),
  first_name: text("first_name"),
  last_name: text("last_name"),
  email: text("email").notNull(),
  status: userStatusEnum("status").default("active"),
});

const mockData = generate(schema);
/** 
 * { id: 1, first_name: 'John', last_name: 'Doe', email: 'john.doe@example.com', status: 'active' }
 */

Options

MockMagic includes options to customize the data generation process.

Custom Key Map

You can map custom keys to recognized data groups. This is useful if you have key names that aren't as direct such as student_first_name which is the same as first_name.

For example: MagicMock recognizes these keys by default:

firstName : first_name, firstName, FirstName, firstname, ...
email : email, emailAddress, email_address, emailaddress, user_email, userEmail, user_email, ...
description : description, Description, desc, descText, ...
color : color, colorCode, colour, colour_code, variant_color, product_color, ...

But student_first_name isn't recognized, so you can map it to the firstName data group. You can map as many keys as you want to a data group, which allows you to generate data for large data sets, or an entire database at once.

const mockData = generate(schema, {
   customKeyMap: {
      firstName: ["student_first_name", "student_name"], // You can map student_first_name to firstName data group
      email: ["student_email"],
    },
});
/** 
 * { id: 1, student_first_name: 'Frank', student_email: 'frank.smith@example.com'},
 * { id: 2, student_first_name: 'Jane', student_email: 'jane.doe@example.com'}

Rounds

You can specify the number of rounds to generate data for:

const mockData = generate(schema, { rounds: 3 }); // Generates 3 sets of mock data
/** 
 * [{ id: 1, name: 'John Doe', email: 'john.doe@example.com', phone: '123-456-7890' },
 *  { id: 2, name: 'Jane Smith', email: 'jane.smith@example.com', phone: '987-654-3210' },
 *  { id: 3, name: 'Bob Johnson', email: 'bob.johnson@example.com', phone: '555-123-4567' }]
 */

Override By Group

You can override the default data generation for data groups to assign them custom values. This is useful for keys like settings or metadata which are often json objects in a specific format.

The values you assign to the data group, will be used for all recognized keys; for example: if you assign a value to settings, the value will be used for keys like user_settings, app_settings, etc.

If you need to only override specific keys, you can use the overrideByKey option.

const mockData = generate(schema, {
  overrideByGroup: {
      settings: { notifications: { email: true } },
      metadata: { device: "mobile" },
    },
});
/** 
 * { id: 1, student_first_name: 'Frank', email: 'frank.smith@example.com', settings: { notifications: { email: true } },
  metadata: { device: "mobile" }},
  { id: 2, student_first_name: 'Jane', email: 'jane.doe@example.com', settings: { notifications: { email: true } },
  metadata: { device: "mobile" }}

Override by Key

You can completely override the default genereated data for specific keys.

This is useful for Enum values or keys like settings or metadata that that require specific values for your application.

You can add any key to the overrideByKey object to assign a specific value to that key.

You can also use the random() helper function to randomly assign values from an array of values.

import { generate, random } from "mockmagic"; // Import the random function

const mockData = generate(schema, {
  overrideByKey: {
    status: random(["active", "inactive", "suspended", "archived"]), // The status key will be assigned a random value from the array
    publishing_status: random(["draft", "pending_review", "scheduled"]),
  }
});
/** 
 * { id: 1, name: 'John Doe', email: 'john.doe@example.com', status: 'active' },
 * { id: 2, name: 'Jane Smith', email: 'jane.smith@example.com', status: 'inactive' },
 * { id: 3, name: 'Bob Johnson', email: 'bob.johnson@example.com', status: 'suspended' },
 */

Skip Keys

You can skip keys to return null values. This is usseful if you want to generate data for some keys but not others.

const mockData = generate(schema, {
  skipKeys: ["phone", "settings"]
});
/** 
 * { id: 1, first_name: "Eric" phone: null, settings: null },
 * { id: 2, first_name: "John" phone: null, settings: null },
 */

Custom Key

You can assign a custom key to overwrite the default generate based on the object key. This is useful if you have an object with keys.

const mockData = generate(schema, {
  customKey: "name"
});

Data type key

You can assign a data type key to fallback to when the key isn't recognized.

const mockData = generate(schema, {
    dataTypeKey: "dataType"
});

Advanced Usage

const mockData = generate(schema, {
  rounds: 3, // Generate 3 sets of mock data
  customKeyMap: {
    firstName: ["user_first_name", "student_name"], // These keys will be regonized as firstName
    email: ["company_email", "user_email"], // These keys will be regonized as email
  },
  overrideByGroup: {
    settings: { device: "mobile" }, // All settings keys will be assigned an object with device: "mobile"
    metadata: { device: "mobile" },
  },
  overrideByKey: {
    status: random(["active", "inactive", "suspended", "archived"]), // Assign random status values
    publishing_status: random(["draft", "pending_review", "scheduled"]),
  },
  skipKeys: ["settings"], // Assign null values to settings keys
});