gistfile1.js

    getDownload(url, body, params) {
        this.query(url, body, params, 'GET').then(resp => {
            resp.blob().then(blob => this.blobDownload(blob, resp));
        });
    }
    blobDownload(blob, resp) {
        const fileName = (resp.headers.get('Content-Disposition') || '').match(/filename="?(.+[^"])"?/)[1]; // matches `filename="a.b"` or `filename=a.b` as 'a.b'
        if (window.navigator && window.navigator.msSaveOrOpenBlob) {
            window.navigator.msSaveOrOpenBlob(blob, fileName);
        } else {
            const url = window.URL.createObjectURL(blob);
            const anchor = document.createElement('a');

            anchor.download = fileName;
            anchor.href = url;
            anchor.style = 'display: none';
            document.body.appendChild(anchor);
            anchor.click();
            setTimeout(() => {
                window.URL.revokeObjectURL(url);
                anchor.remove();
            }, 500);
        }
    }