I am creating an application and when I try to upload an image it gives this error in the console: (node:23) UnhandledPromiseRejectionWarning: Error [ERR\_HTTP\_HEADERS\_SENT]: Cannot set headers after they are sent to the client.
How can I solve this?

My fetch: 

```
let formData = new FormData();
formData.append('arquivo', document.querySelector('input[name="arquivo"]').files[0])
formData.append('candy', candy)
formData.append('theme', document.getElementById('candytheme').value)

fetch('https://nodemae.herokuapp.com/candy', { method: 'post', headers: {'x-auth-token': window.sessionStorage.getItem('token') }, body: formData}).then

```

My server side: 

```
async store(req, res) {
    let candy= req.body.candy;
    let name= uniqid(doce+'-')+'.jpg';
    let route= `/img/${doce}/`;
    let theme= req.body.theme;
    let sampleFile = req.files.arquivo;
    sampleFile.mv(`./public${route}${name}`, function(err){
        if (err) {
            return res.send(err)
        }
    });
    const candy = await Candy.create({
        name: name,
        candy: candy,
        route: route,
        theme: theme
    });

    return res.json(candy);
},

```

The return res.json (candy); returns this:{"errno":-2,"code":"ENOENT","syscall":"open","path":"./public/img/paomel/paomel-q6zynjrg8w45y.jpg"}

[![enter image description here](https://i.stack.imgur.com/9fo2o.png)](https://i.stack.imgur.com/9fo2o.png)