如前所述，filesaver是在客户端处理文件的一个很棒的包。但是，它不能很好地处理大文件。streamsave .js是一个可以处理大文件的替代解决方案(在FileServer.js中指向):

const fileStream = streamSaver.createWriteStream('filename.txt', size);
const writer = fileStream.getWriter();
for(var i = 0; i < 100; i++){
    var uint8array = new TextEncoder("utf-8").encode("Plain Text");
    writer.write(uint8array);
}
writer.close()

var element = document.createElement('a');
element.setAttribute('href', 'data:text/text;charset=utf-8,' +      encodeURI(data));
element.setAttribute('download', "fileName.txt");
element.click();

以下方法适用于IE10+、Edge、Opera、FF和Chrome浏览器:

const saveDownloadedData = (fileName, data) => {
    if(~navigator.userAgent.indexOf('MSIE') || ~navigator.appVersion.indexOf('Trident/')) { /* IE9-11 */
        const blob = new Blob([data], { type: 'text/csv;charset=utf-8;' });
        navigator.msSaveBlob(blob, fileName);
    } else {
        const link = document.createElement('a')
        link.setAttribute('target', '_blank');
        if(Blob !== undefined) {
            const blob = new Blob([data], { type: 'text/plain' });
            link.setAttribute('href', URL.createObjectURL(blob));
        } else {
            link.setAttribute('href', 'data:text/plain,' + encodeURIComponent(data));
        }

        ~window.navigator.userAgent.indexOf('Edge')
            && (fileName = fileName.replace(/[&\/\\#,+$~%.'':*?<>{}]/g, '_')); /* Edge */

        link.setAttribute('download', fileName);
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
    }
}

因此，只需调用函数:

saveDownloadedData('test.txt', 'Lorem ipsum');

如果你只是想把一个字符串转换成可以下载的，你可以使用jQuery尝试一下。

$('a.download').attr('href', 'data:application/csv;charset=utf-8,' + encodeURI(data));

function download(filename, text) {
  var element = document.createElement('a');
  element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(text));
  element.setAttribute('download', filename);

  element.style.display = 'none';
  document.body.appendChild(element);

  element.click();

  document.body.removeChild(element);
}



// Start file download.
download("hello.txt","This is the content of my file :)");

原文:https://ourcodeworld.com/articles/read/189/how-to-create-a-file-and-generate-a-download-with-javascript-in-the-browser-without-a-server

以下方法适用于IE11+、Firefox 25+和Chrome 30+浏览器:

<a id="export" class="myButton" download="" href="#">export</a>
<script>
    function createDownloadLink(anchorSelector, str, fileName){
        if(window.navigator.msSaveOrOpenBlob) {
            var fileData = [str];
            blobObject = new Blob(fileData);
            $(anchorSelector).click(function(){
                window.navigator.msSaveOrOpenBlob(blobObject, fileName);
            });
        } else {
            var url = "data:text/plain;charset=utf-8," + encodeURIComponent(str);
            $(anchorSelector).attr("download", fileName);               
            $(anchorSelector).attr("href", url);
        }
    }

    $(function () {
        var str = "hi,file";
        createDownloadLink("#export",str,"file.txt");
    });

</script>

详见行动:http://jsfiddle.net/Kg7eA/

Firefox和Chrome支持数据URI导航，这允许我们通过导航到数据URI来创建文件，而IE出于安全考虑不支持它。

另一方面，IE有用于保存blob的API，可以用来创建和下载文件。