How to download file from server

 First we have to define a function and then call the function on click. 

Below is an example of the downloading a file.  Create a folder name "downloadformat" in public folder

const onClickExport = () => {
    const link = document.createElement("a");
    link.href = `${window.location.origin}/downloadformat/xxxx.csv`;
    link.setAttribute("download", `download-format.csv`);
    document.body.appendChild(link);
    link.click();
  };
 
<button
className="btn btn-custom btn-secondary buttons-html5"
type="button"
onClick={onClickExport}
>Download Format</button>