Achieve invisible upload in React Uploader component

30 Jan 20238 minutes to read

You can achieve the invisible upload feature by using the selected event in uploader component. Refer to the following example.

index.jsx

import { createElement } from '@syncfusion/ej2-base';
import { UploaderComponent } from '@syncfusion/ej2-react-inputs';
import * as React from 'react';
import * as ReactDOM from "react-dom";
export default class App extends React.Component {
    uploadObj;
    path = {
        removeUrl: 'https://services.syncfusion.com/react/production/api/FileUploader/Remove',
        saveUrl: 'https://services.syncfusion.com/react/production/api/FileUploader/Save'
    };
    dropAreaRef;
    previewRef;
    onCreated() {
        this.uploadObj.dropArea = this.dropAreaRef;
        this.uploadObj.dataBind();
    }
    onupload(args) {
        for (const i of args.filesData) {
            const liparentDiv = createElement('div', { className: 'image-list' });
            const liImage = createElement('img', { className: 'image' });
            liparentDiv.appendChild(liImage);
            this.readURL(liImage, i);
            this.previewRef.appendChild(liparentDiv);
        }
        args.cancel = true;
    }
    readURL(liImage, file) {
        const imgPreview = liImage;
        const imageFile = file.rawFile;
        const reader = new FileReader();
        reader.addEventListener('load', () => {
            imgPreview.src = reader.result;
        }, false);
        if (imageFile) {
            reader.readAsDataURL(imageFile);
        }
    }
    ;
    render() {
        return (<div className='control-pane' ref={dropAreaEle => this.dropAreaRef = dropAreaEle}>
        <div className='control-section row uploadpreview'>
        <div className='col-lg-9'>
        <div className='upload_wrapper'>
        <div id='preview' ref={previewEle => this.previewRef = previewEle}/>
            {/* Render Uploader */}
            <UploaderComponent id='fileUpload' type='file' ref={upload => { this.uploadObj = upload; }} asyncSettings={this.path} selected={this.onupload = this.onupload.bind(this)} locale={'en-US'} allowedExtensions='.png, .jpg, .jpeg' created={this.onCreated = this.onCreated.bind(this)}/>
        </div>
        </div>
        </div>
      </div>);
    }
}
ReactDOM.render(<App />, document.getElementById('fileupload'));

index.tsx

import { createElement } from '@syncfusion/ej2-base';
import { SelectedEventArgs, UploaderComponent } from '@syncfusion/ej2-react-inputs';
import * as React from 'react';
import * as ReactDOM from "react-dom";

export default class App extends React.Component<{}, {}> {
  public uploadObj: UploaderComponent;
  public path: object = {
      removeUrl: 'https://services.syncfusion.com/react/production/api/FileUploader/Remove',
      saveUrl: 'https://services.syncfusion.com/react/production/api/FileUploader/Save'
  }
  private dropAreaRef: HTMLElement;
  private previewRef: HTMLElement;
  public onCreated(): void {
      this.uploadObj.dropArea = this.dropAreaRef;
      this.uploadObj.dataBind();
  }
  public onupload(args: SelectedEventArgs){
  for(const i of args.filesData){
          const liparentDiv = createElement('div',  { className: 'image-list'});
          const liImage = createElement('img',  { className: 'image'});
          liparentDiv.appendChild(liImage);
          this.readURL(liImage, i);
          this.previewRef.appendChild(liparentDiv);
      }
      args.cancel=true;

  }
  public readURL(liImage: HTMLElement, file: any): void {
      const imgPreview: HTMLImageElement = liImage as HTMLImageElement;
      const imageFile: File = file.rawFile;
      const reader: FileReader = new FileReader();
      reader.addEventListener( 'load', () => {
          imgPreview.src = reader.result as string;
      }, false);
      if (imageFile) {
          reader.readAsDataURL(imageFile);
      }
  };
  public render(): JSX.Element {
    return (
        <div className = 'control-pane'  ref={dropAreaEle => this.dropAreaRef = dropAreaEle!}>
        <div className='control-section row uploadpreview'>
        <div className='col-lg-9'>
        <div className='upload_wrapper'>
        <div id='preview' ref={previewEle => this.previewRef = previewEle!}/>
            {/* Render Uploader */}
            <UploaderComponent id='fileUpload' type='file' ref = {upload => {this.uploadObj = upload !}}
            asyncSettings = {this.path}
            selected={ this.onupload=this.onupload.bind(this)} locale= {'en-US'} allowedExtensions= '.png, .jpg, .jpeg' created={this.onCreated = this.onCreated.bind(this)} />
        </div>
        </div>
        </div>
      </div>
        )
    }
}

ReactDOM.render(<App />, document.getElementById('fileupload'));

You can also explore React File Upload feature tour page for its groundbreaking features. You can also explore our React File Upload example to understand how to browse the files which you want to upload to the server.