CODE EXAMPLE FOR JAVASCRIPT

react download file from express res.download

let downloadHandler = (e) =>{
      const fileName = e.target.parentElement.id;
    axios({
        method: 'get',
        url: 'http://localhost:3001/download/'+fileName,
        responseType: 'blob',
        headers: {},
        })
        .then((res) => {
            const url = window.URL.createObjectURL(new Blob([res.data]));
            const link = document.createElement('a');
            link.href = url;
            link.setAttribute('download', fileName);
            document.body.appendChild(link);
            link.click();
        })
        .catch((error) => {
            alert(error);
        })
  }