Cancel Method Not working

[ebeliejinfren]

i use rn-fetch-blob to download file in React Native every thing work correct but when use cancel method according to doc, cancelling not work and got error "fileFetchPromise Is Not Defained"

const download = () => {
  let fileOptions = { fileCache: true, path: path, };
  const fileFetchPromise = config(fileOptions).fetch('GET', fileUrl);
  fileFetchPromise.progress({ interval : 1000 }, (received, total) => {
    let persend = 100 * received / total;
    setSaved(persend.toFixed(0));
    setReceived(bytesToSize(received));
    setTotalSize(bytesToSize(total));
  });

  fileFetchPromise.then((data) => {
    setSaved('100');
  }).catch((err) => {
    setSaved('0')
  })
}

const cancelDownload = () => {
  fileFetchPromise.cancel((err) => {})
}

[nadav2051]

fixed it in my fork, you can look:
nadav2051@6af66cb
nadav2051@f979791

[majirosstefan]

@nadav2051 Not working, I used this patch-package diff:

diff --git a/node_modules/rn-fetch-blob/polyfill/Fetch.js b/node_modules/rn-fetch-blob/polyfill/Fetch.js
index 3ecb591..979f714 100644
--- a/node_modules/rn-fetch-blob/polyfill/Fetch.js
+++ b/node_modules/rn-fetch-blob/polyfill/Fetch.js
@@ -40,6 +40,7 @@ class RNFetchBlobFetchPolyfill {
           promise = Blob.build(body).then((b) => {
             blobCache = b
             options.headers['Content-Type'] = 'multipart/form-data;boundary=' + b.multipartBoundary
+            options.headers['content-type'] = 'multipart/form-data;boundary=' + b.multipartBoundary
             return Promise.resolve(RNFetchBlob.wrap(b._ref))
           })
         }
@@ -58,10 +59,14 @@ class RNFetchBlobFetchPolyfill {
       // task.then is not, so we have to extend task.then with progress and
       // cancel function
       let progressHandler, uploadHandler, cancelHandler
+
+      let scopedTask = null
+
       let statefulPromise = promise
           .then((body) => {
             let task = RNFetchBlob.config(config)
-              .fetch(options.method, url, options.headers, body)
+                .fetch(options.method, url, options.headers, body)
+            scopedTask = task
             if(progressHandler)
               task.progress(progressHandler)
             if(uploadHandler)
@@ -86,12 +91,11 @@ class RNFetchBlobFetchPolyfill {
       }
       statefulPromise.cancel = () => {
         cancelHandler = true
-        if(task.cancel)
-          task.cancel()
+        if(scopedTask && scopedTask.cancel)
+          scopedTask.cancel()
       }
 
       return statefulPromise
-
     }
   }