feat(upload): emit event on file upload start (#462)

Author: sebastian-wec

src/lib/api/upload/upload.ts

@@ -131,6 +131,7 @@ export class Upload extends EventEmitter {
 
     this.uploader.setUploadTags(options.tags);
 
+    this.uploader.on('start', () => this.emit('start'));
     this.uploader.on('error', (e) => this.emit('error', e));
     this.uploader.on('progress', this.handleProgress.bind(this));
   }

src/lib/api/upload/uploaders/s3.ts

@@ -364,6 +364,7 @@ export class S3Uploader extends UploaderAbstract {
       );
 
       debug(`[${id}] All tasks for %s enqueued. Start processing main upload queue`, id);
+      this.emit('start');
       this.partsQueue.start();
 
       resolve(await this.partsQueue.onIdle());

src/lib/client.ts

@@ -457,6 +457,7 @@ export class Client extends EventEmitter {
       upload.setSecurity(security);
     }
 
+    upload.on('start', () => this.emit('upload.start'));
     /* istanbul ignore next */
     upload.on('error', e => {
       if (this.forwardErrors) {
@@ -522,6 +523,7 @@ export class Client extends EventEmitter {
       upload.setSecurity(security);
     }
 
+    upload.on('start', () => this.emit('upload.start'));
     /* istanbul ignore next */
     upload.on('error', e => {
       Sentry.withScope(scope => {

src/lib/picker.ts

@@ -172,6 +172,9 @@ export interface PickerResponse {
 export interface PickerFileCallback {
   (file: PickerFileMetadata): void | Promise<any>;
 }
+export interface PickerFileWithTokenCallback {
+  (file: PickerFileMetadata, token?: {pause?: () => void, resume?: () => void, cancel?: () => void}): void | Promise<any>;
+}
 
 export interface PickerFileCancelCallback {
   (file: PickerFileMetadata): void;
@@ -624,7 +627,7 @@ export interface PickerOptions {
   /**
    * Called when a file begins uploading.
    */
-  onFileUploadStarted?: PickerFileCallback;
+  onFileUploadStarted?: PickerFileWithTokenCallback;
   /**
    * Called when a file is done uploading.
    */