@uppy/xhr-upload: allow custom error message in onAfterResponse

packages/@uppy/utils/src/fetcher.ts

@@ -84,6 +84,16 @@ export function fetcher(
     // eslint-disable-next-line no-async-promise-executor
     return new Promise(async (resolve, reject) => {
       const xhr = new XMLHttpRequest()
+      const onError = (error: Error) => {
+        if (shouldRetry(xhr) && retryCount < retries) {
+          setTimeout(() => {
+            requestWithRetry(retryCount + 1).then(resolve, reject)
+          }, delay(retryCount))
+        } else {
+          timer.done()
+          reject(error)
+        }
+      }
 
       xhr.open(method, url, true)
       xhr.withCredentials = withCredentials
@@ -99,7 +109,15 @@ export function fetcher(
       })
 
       xhr.onload = async () => {
-        await onAfterResponse(xhr, retryCount)
+        try {
+          await onAfterResponse(xhr, retryCount)
+        } catch (err) {
+          // This is important as we need to emit the xhr
+          // over the upload-error event.
+          err.request = xhr
+          onError(err)
+          return
+        }
 
         if (xhr.status >= 200 && xhr.status < 300) {
           timer.done()
@@ -114,16 +132,7 @@ export function fetcher(
         }
       }
 
-      xhr.onerror = () => {
-        if (shouldRetry(xhr) && retryCount < retries) {
-          setTimeout(() => {
-            requestWithRetry(retryCount + 1).then(resolve, reject)
-          }, delay(retryCount))
-        } else {
-          timer.done()
-          reject(new NetworkError(xhr.statusText, xhr))
-        }
-      }
+      xhr.onerror = () => onError(new NetworkError(xhr.statusText, xhr))
 
       xhr.upload.onprogress = (event: ProgressEvent) => {
         timer.progress()

packages/@uppy/xhr-upload/src/index.test.ts

@@ -79,7 +79,14 @@ describe('XHRUpload', () => {
       id: 'XHRUpload',
       endpoint: 'https://fake-endpoint.uppy.io',
       shouldRetry,
+      async onAfterResponse(xhr) {
+        if (xhr.status === 400) {
+          // We want to test that we can define our own error message
+          throw new Error(JSON.parse(xhr.responseText).message)
+        }
+      },
     })
+
     const id = core.addFile({
       type: 'image/png',
       source: 'test',
@@ -95,7 +102,7 @@ describe('XHRUpload', () => {
 
     await Promise.all([
       core.upload(),
-      event.then(([file, , response]) => {
+      event.then(([file, error, response]) => {
         const newFile = core.getFile(id)
         // error and response are set inside upload-error in core.
         // When we subscribe to upload-error it is emitted before
@@ -107,6 +114,7 @@ describe('XHRUpload', () => {
         // might have changed in the meantime
         expect(file).toEqual(newFile)
         expect(response).toBeInstanceOf(XMLHttpRequest)
+        expect(error.message).toEqual('Oh no')
       }),
     ])
 

packages/@uppy/xhr-upload/src/index.ts

@@ -82,7 +82,7 @@ declare module '@uppy/core' {
 }
 
 function buildResponseError(
-  xhr: XMLHttpRequest,
+  xhr?: XMLHttpRequest,
   err?: string | Error | NetworkError,
 ) {
   let error = err
@@ -255,17 +255,15 @@ export default class XHRUpload<
           if (error.name === 'AbortError') {
             return undefined
           }
-          if (error instanceof NetworkError) {
-            const request = error.request!
-
-            for (const file of files) {
-              this.uppy.emit(
-                'upload-error',
-                this.uppy.getFile(file.id),
-                buildResponseError(request, error),
-                request,
-              )
-            }
+          const request = error.request as XMLHttpRequest | undefined
+
+          for (const file of files) {
+            this.uppy.emit(
+              'upload-error',
+              this.uppy.getFile(file.id),
+              buildResponseError(request, error),
+              request,
+            )
           }
 
           throw error