@fluentfixture/core

A flexible tool for generating customizable mock data with fluent interface 🚀

Philosophy

In Informatics, dummy data is benign information that does not contain any useful data, but serves to reserve space where real data is nominally present. Dummy data can be used as a placeholder for both testing and operational purposes. For testing, dummy data can also be used as stubs or pad to avoid software testing issues by ensuring that all variables and data fields are occupied. (↪wiki)

Generating dummy data is crucial in software development. The quality of test data directly impacts development quality and velocity. There are many dummy data generators in the JavaScript ecosystem. However, creating complex objects and responding to real-world use cases can be challenging.

The @fluentfixture aims to provide a fluent interface and an extensible architecture for generating dummy data.

The @fluentfixture doesn't provide predefined data like FakerJS but offers multiple adapters for integration with external libraries.

Documentation

Visit https://docs.fluentfixture.com to view the full documentation.

Introduction

Core (@fluentfixture/core)

The @fluentfixture/core provides various data generators for different use cases. All generators offer a fluent interface for manipulating data, including sorting, creating conditional values, and more.

Installation

$ npm install @fluentfixture/core

Example

Let us consider the following requirements. We need;

• One hundred products that are ordered by their prices,
• Each product has a price that ends with .95,
• Each product has a code field with the "id-color" format calculated using generated values,
• Each product has the same parent category with random id and name but the same type.
• Half of them have stock.

import { alphabetic, bool, hex, int, obj, pick } from '@fluentfixture/core';

// Defines a price generator with amount and the currency fields.
const price = obj({
  amount: int(100, 1000).add(0.95),
  currency: pick(['USD', 'EUR', 'GBP', 'TRY']),
});

// Defines a color generator. (hex + pad + uppercase)
const color = hex(6).padStart(7, '#').upperCase();

// Defines a category with constant id.
const category = obj({
  id: int(1, 100),
  name: alphabetic().headerCase(),
  type: alphabetic(4, 8).memo()
})

// Defines a product generator.
const product = obj({
  id: int(1, 999),
  name: alphabetic(10, 20).capitalCase(),
  category: category,
  description: alphabetic(20, 40).optional(),
  hasStock: bool(0.5),
  color: color,
  price: price,
});

// 1) Adds 'code' field using generated values.
// 2) Iterates the model.
// 3) Sorts the generated models by their prices.
const products = product
  .lazy('code', (p) => `${p.id}-${p.color}`)
  .array(10)
  .sort((a, b) => a.price.amount - b.price.amount);

// Print all products
console.log(products.single());

// Print details of the first product.
console.log(product.format('[${id}] ${name:titleCase()} => ${price.amount}'));

Format (@fluentfixture/format)

The @fluentfixture/format is a flexible string format library that provides formatting functionality with extensible formatting capability.

Installation

$ npm install @fluentfixture/format

Example

import { format } from '@fluentfixture/format';

const source = {
  name: 'john',
  surname: 'doe',
  email: '[e-mail]',
  birthdate: new Date(1_617_258_460_000),
  balance: {
    amount: 120,
    currency: 'USD',
  },
  memberships: ['regular user', 'pro user'],
};

console.log(
  format('${surname}, ${name} <${balance.amount} ${balance.currency}>', source),
);

console.log(
  format('${surname:upperCase()}, ${name:capitalCase()} <${balance.amount} ${balance.currency}>', source),
);

console.log(
  format('${surname:upperCase()}, ${name:capitalCase()} BIRTH_DATE=${birthdate:date("MM-DD-YYYY")}', source),
);

console.log(
  format('${name}.${surname} > MEMBERSHIP=${memberships.0:dotCase()|upperCase()}', source),
);

console.log(
  format('NICKNAME=${name:padStart(7, "#")|padEnd(10,"#")}', source),
);

License

@fluentfixture is MIT licensed.