javascript - 如何将文件名和文件扩展名添加到将 JSON 数组导出到 CSV 字符串然后导出到 javascript 文件的 window.open 方法？

Question

我有以下代码，是在以下问题中找到的: https://stackoverflow.com/a/4130939/1055971

function DownloadJSON2CSV(objArray)
{
    var array = typeof objArray != 'object' ? JSON.parse(objArray) : objArray;

    var str = '';

    for (var i = 0; i < array.length; i++) {
        var line = '';

        for (var index in array[i]) {
            line += array[i][index] + ',';
        }

        line.slice(0,line.Length-1); 

        str += line + '\r\n';
    }

    window.open( "data:text/csv;charset=utf-8," + escape(str))

}

此代码运行良好。它下载文件并保存，但问题是没有办法为文件添加自定义标题，而且文件保存时没有扩展名。 例如，调用保存功能时，文件名默认为“下载”，没有文件扩展名。当我通过 windows 文件系统(如 .csv)添加扩展名并打开文件时同样，所有数据都被完美保存。
我希望找到一种在下载发生之前预设文件名和文件类型的方法。有什么想法吗？

Answer 1

创建不可见链接元素( anchor 标记)并使用所需文件名初始化 a 元素的 download 属性并附加到新创建的窗口中，打开并以编程方式调用创建的 a 元素上的点击事件。

$(document).ready(function(){
    $('button').click(function(){
        var data = $('#txt').val();
        if(data == '')
            return;
        
        JSONToCSVConvertor(data, "Sample Report", true);
    });
});

function JSONToCSVConvertor(JSONData, ReportTitle, ShowLabel) {
    //If JSONData is not an object then JSON.parse will parse the JSON string in an Object
    var arrData = typeof JSONData != 'object' ? JSON.parse(JSONData) : JSONData;
    
    var CSV = '';    
    //Set Report title in first row or line
    
    CSV += ReportTitle + '\r\n\n';

    //This condition will generate the Label/Header
    if (ShowLabel) {
        var row = "";
        
        //This loop will extract the label from 1st index of on array
        for (var index in arrData[0]) {
            
            //Now convert each value to string and comma-seprated
            row += index + ',';
        }

        row = row.slice(0, -1);
        
        //append Label row with line break
        CSV += row + '\r\n';
    }
    
    //1st loop is to extract each row
    for (var i = 0; i < arrData.length; i++) {
        var row = "";
        
        //2nd loop will extract each column and convert it in string comma-seprated
        for (var index in arrData[i]) {
            row += '"' + arrData[i][index] + '",';
        }

        row.slice(0, row.length - 1);
        
        //add a line break after each row
        CSV += row + '\r\n';
    }

    if (CSV == '') {        
        alert("Invalid data");
        return;
    }   
    
    //Generate a file name
    var fileName = "MyReport_";
    //this will remove the blank-spaces from the title and replace it with an underscore
    fileName += ReportTitle.replace(/ /g,"_");   
    
    //Initialize file format you want csv or xls
    var uri = 'data:text/csv;charset=utf-8,' + escape(CSV);
    
    // Now the little tricky part.
    // you can use either>> window.open(uri);
    // but this will not work in some browsers
    // or you will not get the correct file extension    
    
    //this trick will generate a temp <a /> tag
    var link = document.createElement("a");    
    link.href = uri;
    
    //set the visibility hidden so it will not effect on your web-layout
    link.style = "visibility:hidden";
    link.download = fileName + ".csv";
    
    //this part will append the anchor tag and remove it after automatic click
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
}

.txtarea{
    max-width:100%;
    min-height:200px;    
    display:block;
    width:100%;
}

.mydiv{
    padding:10px;
}

.gen_btn{
    padding:5px;
    background-color:#743ED9;
    color:white;
    font-family:arial;
    font-size:13px;
    border:2px solid black;
}

.gen_btn:hover{
    background-color:#9a64ff;
}

<div class='mydiv'>    
    <textarea id="txt" class='txtarea'>[{"Vehicle":"BMW","Date":"30, Jul 2013 09:24 AM","Location":"Hauz Khas, Enclave, New Delhi, Delhi, India","Speed":42},{"Vehicle":"Honda CBR","Date":"30, Jul 2013 12:00 AM","Location":"Military Road,  West Bengal 734013,  India","Speed":0},{"Vehicle":"Supra","Date":"30, Jul 2013 07:53 AM","Location":"Sec-45, St. Angel's School, Gurgaon, Haryana, India","Speed":58},{"Vehicle":"Land Cruiser","Date":"30, Jul 2013 09:35 AM","Location":"DLF Phase I, Marble Market, Gurgaon, Haryana, India","Speed":83},{"Vehicle":"Suzuki Swift","Date":"30, Jul 2013 12:02 AM","Location":"Behind Central Bank RO, Ram Krishna Rd by-lane, Siliguri, West Bengal, India","Speed":0},{"Vehicle":"Honda Civic","Date":"30, Jul 2013 12:00 AM","Location":"Behind Central Bank RO, Ram Krishna Rd by-lane, Siliguri, West Bengal, India","Speed":0},{"Vehicle":"Honda Accord","Date":"30, Jul 2013 11:05 AM","Location":"DLF Phase IV, Super Mart 1, Gurgaon, Haryana, India","Speed":71}]</textarea>
    <button class='gen_btn'>Generate File</button>
</div>