Core ConceptsOverview

Core Concepts

Understanding the fundamental concepts behind MockMaster.

MockMaster is built around several core concepts that work together to provide type-safe API mocking with record and replay capabilities. This section explains each concept in detail.

Main Concepts

Record & Replay

The record and replay pattern is at the heart of MockMaster. Learn how to capture real API responses and replay them deterministically in your tests.

Key topics:

  • Creating recordings from API responses
  • Building replay handlers
  • Request matching and response generation

Scenarios & Recordings

A scenario is a named collection of recorded API interactions. A recording captures a single HTTP request and its corresponding response.

Key topics:

  • Creating and managing scenarios
  • Adding recordings to scenarios
  • Storing scenarios as JSON files
  • Version control best practices

Factory System

MockMaster’s factory system provides a powerful way to generate realistic, customizable test data using Faker.js.

Key topics:

  • Defining factories for your data models
  • Building single objects and lists
  • Overriding default values
  • Using sequences for unique IDs

OpenAPI Integration

MockMaster can automatically generate realistic mock data from OpenAPI 3.0 specifications.

Key topics:

  • Parsing JSON and YAML specs
  • Generating scenarios from schemas
  • Extracting operations
  • Working with complex schemas

Path Matching

MockMaster’s core package provides powerful path matching capabilities for HTTP routing.

Key topics:

  • Exact path matching
  • Path parameters (e.g., /users/:id)
  • Wildcard matching (e.g., /api/*)
  • Parameter extraction

How They Work Together

Here’s how these concepts work together in a typical workflow:

// 1. Parse OpenAPI spec (OpenAPI Integration)
import { parseYaml } from '@mockmaster/openapi'
const spec = parseYaml(`...`)
 
// 2. Generate scenario with recordings (Scenarios & Recordings)
import { generateScenariosFromSpec } from '@mockmaster/cli'
const scenarios = generateScenariosFromSpec(spec, 'user-api')
 
// 3. Create replay handler (Record & Replay)
import { createReplayHandler } from '@mockmaster/msw-adapter'
const handler = createReplayHandler(scenarios[0])
 
// 4. Match paths and replay responses (Path Matching)
const response = handler({ method: 'GET', path: '/users/123' })
 
// 5. Optionally generate custom data with factories (Factory System)
import { defineFactory, build, fake } from '@mockmaster/data'
const userFactory = defineFactory('user', {
  id: (ctx) => ctx.sequence('user'),
  name: () => fake.person.fullName()
})
const customUser = build(userFactory)

Next Steps

Dive deeper into each concept:

Quick StartRecord & Replay