Merge pull request #1 from Karankang007/Karankang007-patch-1

Update flow.js

Author: Karanvir Kang

src/flow.js

@@ -23,6 +23,7 @@
    * @param {string|Function} [opts.testMethod]
    * @param {string|Function} [opts.uploadMethod]
    * @param {bool} [opts.prioritizeFirstAndLastChunk]
+   * @param {bool} [opts.allowDuplicateUploads]
    * @param {string|Function} [opts.target]
    * @param {number} [opts.maxChunkRetries]
    * @param {number} [opts.chunkRetryInterval]
@@ -82,6 +83,7 @@
       testMethod: 'GET',
       uploadMethod: 'POST',
       prioritizeFirstAndLastChunk: false,
+      allowDuplicateUploads: false,
       target: '/',
       testChunks: true,
       generateUniqueIdentifier: null,
@@ -568,9 +570,9 @@
         // Uploading empty file IE10/IE11 hangs indefinitely
         // see https://connect.microsoft.com/IE/feedback/details/813443/uploading-empty-file-ie10-ie11-hangs-indefinitely
         // Directories have size `0` and name `.`
-        // Ignore already added files
+        // Ignore already added files if opts.allowDuplicateUploads is set to false
         if ((!ie10plus || ie10plus && file.size > 0) && !(file.size % 4096 === 0 && (file.name === '.' || file.fileName === '.')) &&
-          !this.getFromUniqueIdentifier(this.generateUniqueIdentifier(file))) {
+          (opts.allowDuplicateUploads || !this.getFromUniqueIdentifier(this.generateUniqueIdentifier(file)))) {
           var f = new FlowFile(this, file);
           if (this.fire('fileAdded', f, event)) {
             files.push(f);