Class FetchMock

Wrapper around Cloudflare's fetchMock for declarative fetch mocking in tests

Based on undici's MockAgent, fetchMock.get(origin) returns a MockPool for that origin. The MockPool's intercept() method is used to define which requests to mock.

Example

import { createFetchMock } from '@stratal/testing'

const mock = createFetchMock()

beforeEach(() => {
  mock.activate()
  mock.disableNetConnect()
})

afterEach(() => {
  mock.reset()
})

it('should mock external API', async () => {
  // Using helper method
  mock.mockJsonResponse('https://api.example.com/data', { success: true })

  // Or using direct API
  mock.get('https://api.example.com')
    .intercept({ path: '/users', method: 'POST' })
    .reply(201, JSON.stringify({ created: true }))

  const response = await fetch('https://api.example.com/data')
  const json = await response.json()

  expect(json.success).toBe(true)
  mock.assertNoPendingInterceptors()
})

Index

Constructors

constructor

Methods

activate assertNoPendingInterceptors deactivate disableNetConnect enableNetConnect get mockError mockJsonResponse mockRequest reset

Constructors

constructor

new FetchMock(): FetchMock
Returns FetchMock

Methods

activate

activate(): void
Activate fetch mocking for the current test

Returns void
Example
```
beforeEach(() => {
  mock.activate()
})
```
- Defined in packages/testing/src/core/http/fetch-mock.ts:83

assertNoPendingInterceptors

assertNoPendingInterceptors(): void

Assert that all defined interceptors were called

Returns void

Throws

If there are pending interceptors that weren't matched

Example

it('should call all mocked endpoints', async () => {
  mock.mockJsonResponse('https://api.example.com/data', { data: [] })

  await fetch('https://api.example.com/data')

  mock.assertNoPendingInterceptors() // Pass
})

deactivate

deactivate(): void
Deactivate fetch mocking

Returns void
- Defined in packages/testing/src/core/http/fetch-mock.ts:90

disableNetConnect

disableNetConnect(): void
Disable all network connections, forcing all requests to use mocks

Returns void
Example
```
beforeEach(() => {
  mock.activate()
  mock.disableNetConnect() // Ensure all requests are mocked
})
```
- Defined in packages/testing/src/core/http/fetch-mock.ts:105

enableNetConnect

enableNetConnect(host?: string | RegExp): void
Enable network connections for specific hosts
Parameters
- Optionalhost: string | RegExp
Returns void
Example
```
mock.enableNetConnect('localhost')
mock.enableNetConnect(/^https://trusted\.com/)
```
- Defined in packages/testing/src/core/http/fetch-mock.ts:118

get

get(origin: string): Interceptable

Get a MockPool for the specified origin

This is the underlying fetchMock.get() method that returns a MockPool for mocking requests to the specified origin.

Parameters

origin: string
The origin URL (e.g., 'https://api.example.com')

Returns Interceptable

MockPool for chaining .intercept() and .reply()

Example

// Mock a GET request
mock.get('https://api.example.com')
  .intercept({ path: '/users', method: 'GET' })
  .reply(200, JSON.stringify({ users: [] }))

// Mock a POST request with body matching
mock.get('https://api.example.com')
  .intercept({
    path: '/users',
    method: 'POST',
    body: (body) => body.includes('test')
  })
  .reply(201, JSON.stringify({ created: true }))

mockError

mockError(
    url: string,
    status: number,
    message?: string,
    options?: MockErrorOptions,
): MockScope<object>
Helper method to mock error responses
Parameters
- url: string
  Full URL to mock
- status: number
  HTTP error status code
- Optionalmessage: string
  Optional error message
- options: MockErrorOptions = {}
  Additional options for the error mock
Returns MockScope<object>
Example
```
// Mock a 401 error
mock.mockError('https://api.example.com/fail', 401, 'Unauthorized')

// Mock a 500 error with custom method
mock.mockError(
  'https://api.example.com/fail',
  500,
  'Server Error',
  { method: 'POST' }
)
```
- Defined in packages/testing/src/core/http/fetch-mock.ts:240

mockJsonResponse

mockJsonResponse(
    url: string,
    data: unknown,
    options?: MockJsonOptions,
): MockScope<object>

Helper method to mock JSON responses

Automatically parses the URL into origin and path, and sets up the mock.

Parameters

url: string
Full URL to mock (e.g., 'https://api.example.com/users')
data: unknown
JSON data to return
options: MockJsonOptions = {}
Additional options for the mock

Returns MockScope<object>

Example

// Mock a GET request
mock.mockJsonResponse('https://api.example.com/users', { users: [] })

// Mock a POST request
mock.mockJsonResponse(
  'https://api.example.com/users',
  { created: true },
  { method: 'POST', status: 201 }
)

// With custom headers and delay
mock.mockJsonResponse(
  'https://api.example.com/users',
  { users: [] },
  {
    status: 200,
    method: 'GET',
    headers: { 'X-Custom': 'value' },
    delay: 100
  }
)

mockRequest

mockRequest(
origin: string,
options: { body?: unknown; method?: string; path: string; status?: number },
): MockScope<object>
Generic helper to mock any HTTP request
Parameters
- origin: string
  The origin URL (e.g., 'https://api.example.com')
- options: { body?: unknown; method?: string; path: string; status?: number }
  Request matching and response options
Returns MockScope<object>
Example
```
mock.mockRequest('https://api.example.com', {
  path: '/users',
  method: 'PUT',
  status: 200,
  body: { updated: true }
})
```
- Defined in packages/testing/src/core/http/fetch-mock.ts:274

reset

reset(): void
Reset all mocks and interceptors

Returns void
Example
```
afterEach(() => {
  mock.reset()
})
```
- Defined in packages/testing/src/core/http/fetch-mock.ts:155

Class FetchMock

Example

Index

Constructors

Methods

Constructors

constructor

Returns FetchMock

Methods

activate

Returns void

Example

assertNoPendingInterceptors

Returns void

Throws

Example

deactivate

Returns void

disableNetConnect

Returns void

Example

enableNetConnect

Parameters

Returns void

Example

get

Parameters

Returns Interceptable

Example

mockError

Parameters

Returns MockScope<object>

Example

mockJsonResponse

Parameters

Returns MockScope<object>

Example

mockRequest

Parameters

Returns MockScope<object>

Example

reset

Returns void

Example

Settings

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