на функции DDROP реагировать параметры Dropzone
onDrop(accepted, rejected, myArgument) {
console.log(accepted, rejected, myArgument)
}
<Dropzone onDrop={(accepted, rejected) => {this.onDrop(accepted, rejected, 'third')}}>
<p>Drop files here...</p>
</Dropzone>
Grieving Gharial