jest-fetch-mock - npm Package Compare versions

Comparing version 1.7.5 to 2.0.0

package.json

 {
   "name": "jest-fetch-mock",
-  "version": "1.7.5",
+  "version": "2.0.0",
   "description": "fetch mock for jest",
@@ -5,0 +5,0 @@ "main": "src/index.js",

README.md

@@ -68,10 +68,27 @@ # Jest Fetch Mock
 
-- `fetch.mockResponse(body, init): fetch` - Mock all fetch calls
-- `fetch.mockResponseOnce(body, init): fetch` - Mock each fetch call independently
-- `fetch.once(body, init): fetch` - Alias for mockResponseOnce
+- `fetch.mockResponse(bodyOrFunction, init): fetch` - Mock all fetch calls
+- `fetch.mockResponseOnce(bodyOrFunction, init): fetch` - Mock each fetch call independently
+- `fetch.once(bodyOrFunction, init): fetch` - Alias for mockResponseOnce
 - `fetch.mockResponses(...responses): fetch` - Mock multiple fetch calls independently
-  - Each argument is an array taking `[body, init]`
-- `fetch.mockReject(error): fetch` - Mock all fetch calls, letting them fail directly
-- `fetch.mockRejectOnce(error): fetch` - Let the next fetch call fail directly
+  - Each argument is an array taking `[bodyOrFunction, init]`
+- `fetch.mockReject(errorOrFunction): fetch` - Mock all fetch calls, letting them fail directly
+- `fetch.mockRejectOnce(errorOrFunction): fetch` - Let the next fetch call fail directly
 
+### Functions
+
+Instead of passing body, it is also possible to pass a function that returns a promise.
+The promise should resolve with an object containing body and init props
+
+i.e:
+
+```
+fetch.mockResponse(() => callMyApi().then(res => ({body: res}))
+```
+
+The same goes for rejects:
+
+```
+fetch.mockReject(() => doMyAsyncJob().then(res => Promise.reject(res.errorToRaise)))
+```
+
 ### Mock utilities
@@ -78,0 +95,0 @@

src/index.d.ts

@@ -13,8 +13,8 @@ declare module "jest-fetch-mock" {
     (input?: string | Request, init?: RequestInit): Promise<Response>;
-    mockResponse(body: string, init?: MockParams): Fetch;
-    mockResponseOnce(body: string, init?: MockParams): Fetch;
+    mockResponse(body: string | Function, init?: MockParams): Fetch;
+    mockResponseOnce(body: string | Function, init?: MockParams): Fetch;
     once(body: string, init?: MockParams): Fetch;
     mockResponses(...responses : Array<[string] | [string, MockParams]>): Fetch;
-    mockReject(error?: Error): Fetch;
-    mockRejectOnce(error?: Error): Fetch;
+    mockReject(error?: Error | Function): Fetch;
+    mockRejectOnce(error?: Error | Function): Fetch;
     resetMocks(): void;
@@ -21,0 +21,0 @@ }

src/index.js

@@ -39,2 +39,12 @@ const crossFetch = require('cross-fetch')
 
+const isFn = unknown => typeof unknown === 'function'
+
+const normalizeResponse = (bodyOrFunction, init) => () => isFn(bodyOrFunction) ?
+    bodyOrFunction().then(({body, init}) => new ResponseWrapper(body, init)) :
+    Promise.resolve(new ResponseWrapper(bodyOrFunction, init))
+
+const normalizeError = errorOrFunction =>  isFn(errorOrFunction) ?
+  errorOrFunction :
+  () => Promise.reject(errorOrFunction)
+
 const fetch = jest.fn()
@@ -44,17 +54,7 @@ fetch.Headers = Headers
 fetch.Request = Request
-fetch.mockResponse = (body, init) => {
-  return fetch.mockImplementation(() =>
-    Promise.resolve(new ResponseWrapper(body, init))
-  )
-}
+fetch.mockResponse = (bodyOrFunction, init) => fetch.mockImplementation(normalizeResponse(bodyOrFunction, init))
 
-fetch.mockReject = error => {
-  return fetch.mockImplementation(() => Promise.reject(error))
-}
+fetch.mockReject = errorOrFunction => fetch.mockImplementation(normalizeError(errorOrFunction))
 
-const mockResponseOnce = (body, init) => {
-  return fetch.mockImplementationOnce(() =>
-    Promise.resolve(new ResponseWrapper(body, init))
-  )
-}
+const mockResponseOnce = (bodyOrFunction, init) => fetch.mockImplementationOnce(normalizeResponse(bodyOrFunction, init))
 
@@ -65,12 +65,6 @@ fetch.mockResponseOnce = mockResponseOnce
 
-fetch.mockRejectOnce = error => {
-  return fetch.mockImplementationOnce(() => Promise.reject(error))
-}
+fetch.mockRejectOnce = errorOrFunction => fetch.mockImplementationOnce(normalizeError(errorOrFunction))
 
 fetch.mockResponses = (...responses) => {
-  responses.forEach(([body, init]) => {
-    fetch.mockImplementationOnce(() =>
-      Promise.resolve(new ResponseWrapper(body, init))
-    )
-  })
+  responses.forEach(([bodyOrFunction, init]) => fetch.mockImplementationOnce(normalizeResponse(bodyOrFunction, init)))
   return fetch
@@ -77,0 +71,0 @@ }

No alert changes

Improved metrics

Total package byte prevSize

204388

increased by0.4%

Number of lines in readme file

488

increased by3.61%

Worsened metrics

Lines of code

573

decreased by-1.55%

No dependency changes