Native Javascript, automatically download a BLOB zip file using FETCH without the use of manual triggering clicking a DOM element. Will create a DOM element automatically and set the attribute HREF to a zip file or contents, then download file automatically on HTML file page load. Or also, will work through Node.js or another Fetch compatible Ja…

download_zip.js

/*
 * @Author Raymond Pittman
 * @Github: https://github.com/raymondpittman
 * @Note: Added README.md https://gist.github.com/raymondpittman/11cc82788422d1bddfaa62e60e5ec9aa
 */

/*
 * @params
 * @download: http://.zip
 * @filename: ./downloaded.zip
 */
function download(url, filename) {
    fetch(url, {
        mode: 'no-cors' 
        /*
        * ALTERNATIVE MODE {
        mode: 'cors'
        }
        *
        */
    }).then((transfer) => {
        return transfer.blob();                 // RETURN DATA TRANSFERED AS BLOB
    }).then((bytes) => {
        let elm = document.createElement('a');  // CREATE A LINK ELEMENT IN DOM
        elm.href = URL.createObjectURL(bytes);  // SET LINK ELEMENTS CONTENTS
        elm.setAttribute('download', filename); // SET ELEMENT CREATED 'ATTRIBUTE' TO DOWNLOAD, FILENAME PARAM AUTOMATICALLY
        elm.click()                             // TRIGGER ELEMENT TO DOWNLOAD
    }).catch((error) => {
        console.log(error);                     // OUTPUT ERRORS, SUCH AS CORS WHEN TESTING NON LOCALLY
    })
}
 
/*
 * @CALL
 * EXAMPLE LOCAL FUNCTION CALL
 */
download('http://.zip', 'test.zip');

Thank you - you saved my day - was trying for a few hours to get this done.
I needed this in a page showing a spinner and redirect back to the issuing page after the download.
Your code made that possible - Just had to a final then

 .then(() => {
        history.back();
      })