If you're still using class components, you can use the [`<Dropzone>`](https://react-dropzone.js.org/#components) component provided by the lib:

```jsx harmony
import React, {Component} from 'react';
import Dropzone from 'react-dropzone';

class Basic extends Component {
  constructor() {
    super();
    this.onDrop = (files) => {
      this.setState({files})
    };
    this.state = {
      files: []
    };
  }

  render() {
    const files = this.state.files.map(file => (
      <li key={file.name}>
        {file.name} - {file.size} bytes
      </li>
    ));

    return (
      <Dropzone onDrop={this.onDrop}>
        {({getRootProps, getInputProps}) => (
          <section className="container">
            <div {...getRootProps({className: 'dropzone'})}>
              <input {...getInputProps()} />
              <p>Drag 'n' drop some files here, or click to select files</p>
            </div>
            <aside>
              <h4>Files</h4>
              <ul>{files}</ul>
            </aside>
          </section>
        )}
      </Dropzone>
    );
  }
}

<Basic />
```