fix(LocalGraphQLClient): handle middleware and responseReducer (#1206)

examples/create-react-app/test/setup.js

@@ -0,0 +1,3 @@
+if (typeof global.Response === 'undefined') {
+  global.Response = function () {}
+}

jest.config.js

@@ -45,7 +45,8 @@ const projects = [
         '\\.[jt]sx?$': 'babel-jest'
       },
       displayName: 'cra-example',
-      testEnvironment: 'jsdom'
+      testEnvironment: 'jsdom',
+      setupFiles: ['<rootDir>/examples/create-react-app/test/setup.js']
     }
   }
 ]

packages/graphql-hooks/src/GraphQLClient.ts

@@ -348,11 +348,11 @@ class GraphQLClient {
           return response.json().then(({ errors, data }) => {
             return this.generateResult<ResponseData, TGraphQLError>({
               graphQLErrors: errors,
-              data:
-                // enrich data with responseReducer if defined
-                typeof options.responseReducer === 'function'
-                  ? options.responseReducer(data, response)
-                  : data,
+              data: applyResponseReducer(
+                options.responseReducer,
+                data,
+                response
+              ),
               headers: response.headers
             })
           })
@@ -466,4 +466,15 @@ function isGraphQLWsClient(value: any): value is GraphQLWsClient {
   return typeof value.subscribe === 'function'
 }
 
+export function applyResponseReducer(
+  responseReducer: RequestOptions['responseReducer'],
+  data,
+  response: Response
+) {
+  // enrich data with responseReducer if defined
+  return typeof responseReducer === 'function'
+    ? responseReducer(data, response)
+    : data
+}
+
 export default GraphQLClient

packages/graphql-hooks/src/LocalGraphQLClient.ts

@@ -1,6 +1,12 @@
-import GraphQLClient from './GraphQLClient'
+import GraphQLClient, { applyResponseReducer } from './GraphQLClient'
 import LocalGraphQLError from './LocalGraphQLError'
-import { LocalClientOptions, LocalQueries, Result } from './types/common-types'
+import {
+  LocalClientOptions,
+  LocalQueries,
+  Operation,
+  RequestOptions,
+  Result
+} from './types/common-types'
 
 /** Local version of the GraphQLClient which only returns specified queries
  * Meant to be used as a way to easily mock and test queries during development. This client never contacts any actual server.
@@ -27,7 +33,7 @@ class LocalGraphQLClient extends GraphQLClient {
   // Delay before sending responses in miliseconds for simulating latency
   requestDelayMs: number
   constructor(config: LocalClientOptions) {
-    super({ url: '', ...config })
+    super({ url: 'http://localhost', ...config })
     this.localQueries = config.localQueries
     this.requestDelayMs = config.requestDelayMs || 0
     if (!this.localQueries) {
@@ -41,29 +47,38 @@ class LocalGraphQLClient extends GraphQLClient {
     // Skips all config verification from the parent class because we're mocking the client
   }
 
-  request<ResponseData = any, TGraphQLError = object, TVariables = object>(
-    operation
-  ): Promise<Result<any, TGraphQLError>> {
-    if (!this.localQueries[operation.query]) {
-      throw new Error(
-        `LocalGraphQLClient: no query match for: ${operation.query}`
-      )
-    }
-    return timeoutPromise(this.requestDelayMs)
-      .then(() =>
-        Promise.resolve(
-          this.localQueries[operation.query](
-            operation.variables,
-            operation.operationName
-          )
+  requestViaHttp<ResponseData, TGraphQLError = object, TVariables = object>(
+    operation: Operation<TVariables>,
+    options: RequestOptions = {}
+  ): Promise<Result<ResponseData, TGraphQLError>> {
+    return timeoutPromise(this.requestDelayMs).then(() => {
+      if (!operation.query || !this.localQueries[operation.query]) {
+        throw new Error(
+          `LocalGraphQLClient: no query match for: ${operation.query}`
         )
+      }
+
+      const data = this.localQueries[operation.query](
+        operation.variables,
+        operation.operationName
       )
+
+      return applyResponseReducer(options.responseReducer, data, new Response())
+    })
+  }
+
+  request<ResponseData, TGraphQLError = object, TVariables = object>(
+    operation: Operation<TVariables>,
+    options?: RequestOptions
+  ): Promise<Result<any, TGraphQLError>> {
+    return super
+      .request<ResponseData, TGraphQLError, TVariables>(operation, options)
       .then(result => {
         if (result instanceof LocalGraphQLError) {
           return { error: result }
         }
-        const { data, errors } = collectErrorsFromObject(result)
-        if (errors.length > 0) {
+        const { data, errors } = collectErrors(result)
+        if (errors && errors.length > 0) {
           return {
             data,
             error: new LocalGraphQLError({
@@ -76,7 +91,6 @@ class LocalGraphQLClient extends GraphQLClient {
       })
   }
 }
-
 function timeoutPromise(delayInMs) {
   return new Promise(resolve => {
     setTimeout(resolve, delayInMs)
@@ -95,7 +109,7 @@ function collectErrorsFromObject(objectIn: object): {
   const errors: Error[] = []
 
   for (const [key, value] of Object.entries(objectIn)) {
-    const child = collectErrorsFromChild(value)
+    const child = collectErrors(value)
     data[key] = child.data
     if (child.errors != null) {
       errors.push(...child.errors)
@@ -113,7 +127,7 @@ function collectErrorsFromArray(arrayIn: object[]): {
   const errors: Error[] = []
 
   for (const [idx, entry] of arrayIn.entries()) {
-    const child = collectErrorsFromChild(entry)
+    const child = collectErrors(entry)
     data[idx] = child.data
     if (child.errors != null) {
       errors.push(...child.errors)
@@ -123,7 +137,7 @@ function collectErrorsFromArray(arrayIn: object[]): {
   return { data, errors }
 }
 
-function collectErrorsFromChild(entry: object) {
+function collectErrors(entry: object) {
   if (entry instanceof Error) {
     return { data: null, errors: [entry] }
   } else if (Array.isArray(entry)) {

packages/graphql-hooks/test-jsdom/unit/LocalGraphQLClient.test.tsx

@@ -29,6 +29,10 @@ const QUERY_PARTIAL_ERROR_WITH_ARRAY = {
   query: 'PartialErrorQueryWithArray'
 }
 
+const QUERY_ARRAY = {
+  query: 'ArrayQuery'
+}
+
 const HooksTestQuery = `
 query {
   testQuery {
@@ -54,15 +58,19 @@ const localQueries = {
   PartialErrorQuery: () => ({
     property1: 'Hello World',
     property2: new Error('failed to resolve property 2'),
-    nested: {property3: new Error('failed to resolve nested property 3'), property4: 'Hello again'}
+    nested: {
+      property3: new Error('failed to resolve nested property 3'),
+      property4: 'Hello again'
+    }
   }),
   PartialErrorQueryWithArray: () => ({
     property1: 'Hello World',
     arrayProperty: [
-      {item: 'Hello item'},
+      { item: 'Hello item' },
       new Error('failed to resolve child of array')
     ]
   }),
+  ArrayQuery: () => [{ item: 'Hello item' }],
   [HooksTestQuery]: () => ({
     testQuery: {
       value: 2
@@ -123,7 +131,9 @@ describe('LocalGraphQLClient', () => {
       expect(result.error.graphQLErrors).toEqual(
         expect.arrayContaining([
           expect.objectContaining({ message: 'failed to resolve property 2' }),
-          expect.objectContaining({ message: 'failed to resolve nested property 3' })
+          expect.objectContaining({
+            message: 'failed to resolve nested property 3'
+          })
         ])
       )
     })
@@ -138,10 +148,18 @@ describe('LocalGraphQLClient', () => {
       expect(result.error).toBeDefined()
       expect(result.error.graphQLErrors).toEqual(
         expect.arrayContaining([
-          expect.objectContaining({ message: 'failed to resolve child of array' }),
+          expect.objectContaining({
+            message: 'failed to resolve child of array'
+          })
         ])
       )
     })
+    it('should handle array result', async () => {
+      const result = await client.request(QUERY_ARRAY)
+      expect(result.data).toBeInstanceOf(Array)
+      expect(result.data).toHaveLength(1)
+      expect(result.data[0]).toHaveProperty('item', 'Hello item')
+    })
   })
   describe('integration with hooks', () => {
     let client, wrapper
@@ -159,4 +177,48 @@ describe('LocalGraphQLClient', () => {
       expect(dataNode.textContent).toBe('2')
     })
   })
+  describe('middleware', () => {
+    let client: LocalGraphQLClient
+    const middlewareSpy = jest.fn()
+    const addResponseHookSpy = jest.fn()
+
+    beforeEach(() => {
+      client = new LocalGraphQLClient({
+        localQueries,
+        middleware: [
+          ({ addResponseHook }, next) => {
+            addResponseHook(response => {
+              addResponseHookSpy()
+              return response
+            })
+            middlewareSpy()
+            next()
+          }
+        ]
+      })
+    })
+    it('should run middleware', async () => {
+      const result = await client.request(QUERY_BASIC)
+
+      expect(result.data.hello).toBe('Hello world')
+      expect(middlewareSpy).toHaveBeenCalledTimes(1)
+      expect(addResponseHookSpy).toHaveBeenCalledTimes(1)
+    })
+  })
+  describe('responseReducer option', () => {
+    let client: LocalGraphQLClient
+
+    beforeEach(() => {
+      client = new LocalGraphQLClient({
+        localQueries
+      })
+    })
+    it('should return responseReducer result', async () => {
+      const result = await client.request<string[]>(QUERY_ARRAY, {
+        responseReducer: fetchedData => [...fetchedData, 'foo']
+      })
+
+      expect(result.data).toStrictEqual([{ item: 'Hello item' }, 'foo'])
+    })
+  })
 })