feat(onError): add callback (works for async requests--sync requests …

…just return nothing)

__tests__/index.js

@@ -9,7 +9,6 @@ import req, {
   flushChunkNames
 } from '../src'
 
-
 describe('requireSync: tries to require module synchronously on both the server and client', () => {
   it('babel', () => {
     const modulePath = createPath('es6')
@@ -174,8 +173,23 @@ describe('requireAsync: requires module asynchronously on the client, returning
       expect(error.message).toEqual('ah')
     }
   })
-})
 
+  it('rejected promise calls onError', async () => {
+    const error = new Error('ah')
+    const onError = jest.fn()
+    const opts = { onError }
+    const { requireAsync } = req(Promise.reject(error), opts)
+
+    try {
+      await requireAsync()
+    }
+    catch (error) {
+      expect(error.message).toEqual('ah')
+    }
+
+    expect(onError).toBeCalledWith(error)
+  })
+})
 
 describe('addModule: add moduleId and chunkName for SSR flushing', () => {
   it('babel', () => {
@@ -213,7 +227,10 @@ describe('addModule: add moduleId and chunkName for SSR flushing', () => {
     flushModuleIds() // insure sets are empty:
     flushChunkNames()
 
-    let universal = req(undefined, { resolve: () => moduleEs6, chunkName: 'es6' })
+    let universal = req(undefined, {
+      resolve: () => moduleEs6,
+      chunkName: 'es6'
+    })
     universal.addModule()
 
     universal = req(undefined, { resolve: () => moduleEs5, chunkName: 'es5' })
@@ -230,7 +247,6 @@ describe('addModule: add moduleId and chunkName for SSR flushing', () => {
   })
 })
 
-
 describe('other options', () => {
   it('key (string): resolve export to value of key', () => {
     const modulePath = createPath('es6')
@@ -331,7 +347,6 @@ describe('other options', () => {
   })
 })
 
-
 describe('unit tests', () => {
   test('tryRequire: requires module using key export finder + calls onLoad with module', () => {
     const moduleEs6 = createPath('es6')

src/index.js

@@ -3,19 +3,20 @@ declare var __webpack_require__: Function
 declare var __webpack_modules__: Object
 
 export type ResolveImport = (error: ?any, module: ?any) => void
-export type AsyncFunc = ((ResolveImport, ...args: Array<any>) => Promise<*>)
+export type AsyncFunc = (ResolveImport, ...args: Array<any>) => Promise<*>
 export type AsyncImport = Promise<*> | AsyncFunc
 export type Id = string
 export type Key = string | null | ((module: ?Object) => any)
 export type OnLoad = (module: Object) => void
+export type OnError = (error: Object) => void
 export type PathResolve = Id | (() => Id)
-
 export type Options = {
   resolve?: PathResolve, // only optional when async-only
   chunkName?: string,
   path?: PathResolve,
   key?: Key,
   timeout?: number,
+  onError?: OnError,
   onLoad?: OnLoad,
   initialRequire?: boolean,
   alwaysUpdate?: boolean
@@ -85,11 +86,12 @@ export default (asyncImport: ?AsyncImport, options: Options = {}): Tools => {
     key,
     timeout = 15000,
     onLoad,
+    onError,
     initialRequire = true,
     alwaysUpdate = false
   } = options
 
-  const modulePath = typeof path === 'function' ? path() : (path || '')
+  const modulePath = typeof path === 'function' ? path() : path || ''
 
   let mod
   let weakId
@@ -156,12 +158,11 @@ export default (asyncImport: ?AsyncImport, options: Options = {}): Tools => {
           return
         }
 
-        request
-          .then(m => resolveImport(null, m))
-          .catch(error => {
-            clearTimeout(timer)
-            reject(error)
-          })
+        request.then(m => resolveImport(null, m)).catch(error => {
+          clearTimeout(timer)
+          if (onError) onError(error)
+          reject(error)
+        })
       })
     }