How to set custom DropzoneJS progress value? - reactjs

Question

I am using dropzone-react-component, which is simply a wrapper of DropzoneJS for react.
I added an event that handles uploading like this:
addedfile: file => handleFileUpload(file),
However, the upload progress bar simply goes up and validates the upload, while I can see that the upload is still taking place.
So my question, is, how am I supposed to set my own value for the upload percentage and make it work with the dropzone's own styling?
This is the React component:
constructor(props) {
super(props);
this.componentConfig = {
iconFiletypes: ['.jpg', '.png', '.gif', '.pdf'],
showFiletypeIcon: true,
postUrl: 'no-url',
};
this.eventHandlers = {
addedfile: file => handleFileUpload(file),
};
this.djsConfig = {
autoProcessQueue: false,
dictDefaultMessage: 'Déposez un fichier ici ou cliquez pour en choisir un',
maxFilesize: 200, // MB
clickable: true, // Lets you click the dropzone
acceptedFiles: 'image/*,application/pdf',
renameFileName: this.props.fileRename || 'myFile',
parallelUploads: 1,
uploadMultiple: false,
};
}
render() {
return (
<DropzoneComponent
config={this.componentConfig}
eventHandlers={this.eventHandlers}
djsConfig={this.djsConfig}
/>
}
And this is the code used to upload the file, which uses the package Meteor Slingshot:
const handleFileUpload = (file) => {
var uploader = new Slingshot.Upload("myFileUploads");
uploader.send(file, function (error, downloadUrl) {
if (error) {
// Log service detailed response.
console.log(error);
} else {
console.log(downloadUrl);
}
});
let computation = Tracker.autorun(() => {
if (!isNaN(uploader.progress())) {
console.log(uploader.progress());
}
});
};