feat(layouts): add file uploader (#842)

src/app/theme/components/baFileUploader/baFileUploader.component.ts

@@ -0,0 +1,59 @@
+import { Component, ViewChild, Input, Output, EventEmitter, ElementRef, Renderer } from '@angular/core';
+import { NgUploaderOptions } from 'ngx-uploader';
+@Component({
+  selector: 'ba-file-uploader',
+  styleUrls: ['./baFileUploader.scss'],
+  templateUrl: './baFileUploader.html',
+})
+export class BaFileUploader {
+  @Input() fileUploaderOptions: NgUploaderOptions = { url: '' };
+  @Output() onFileUpload = new EventEmitter<any>();
+  @Output() onFileUploadCompleted = new EventEmitter<any>();
+  @Input() defaultValue: string = '';
+
+  @ViewChild('fileUpload') public _fileUpload: ElementRef;
+  @ViewChild('inputText') public _inputText: ElementRef;
+
+  public uploadFileInProgress: boolean;
+  constructor(private renderer: Renderer) { 
+  }
+
+  bringFileSelector(): boolean {
+    this.renderer.invokeElementMethod(this._fileUpload.nativeElement, 'click');
+    return false;
+  }
+
+  beforeFileUpload(uploadingFile): void {
+    let files = this._fileUpload.nativeElement.files;
+    if (files.length) {
+      const file = files[0];
+      this._onChangeFileSelect(files[0])
+      if (!this._canFleUploadOnServer()) {
+        uploadingFile.setAbort();
+      } else {
+        this.uploadFileInProgress = true;
+      }
+    }
+  }
+
+  _onChangeFileSelect(file) {
+    this._inputText.nativeElement.value = file.name
+  }
+
+  _onFileUpload(data): void {
+    if (data['done'] || data['abort'] || data['error']) {
+      this._onFileUploadCompleted(data);
+    } else {
+      this.onFileUpload.emit(data);
+    }
+  }
+
+  _onFileUploadCompleted(data): void {
+    this.uploadFileInProgress = false;
+    this.onFileUploadCompleted.emit(data);
+  }
+
+  _canFleUploadOnServer(): boolean {
+    return !!this.fileUploaderOptions['url'];
+  }
+}