cos.getObject({
    Bucket: 'examplebucket-1250000000', /* Your bucket name. Required. */
    Region: 'COS_REGION',  /* Bucket region (required), such as ap-beijing */
    Key: '1.jpg',  /* Object key stored in the bucket (such as `1.jpg` and `a/b/test.txt`). Required. */
    onProgress: function (progressData) {
        console.log(JSON.stringify(progressData));
    }
}, function(err, data) {
    console.log(err || data.Body);
});

cos.getObject({
    Bucket: 'examplebucket-1250000000', /* Your bucket name. Required. */
    Region: 'COS_REGION',  /* Bucket region (required), such as ap-beijing */
    Key: '1.jpg',  /* Object key stored in the bucket (such as `1.jpg` and `a/b/test.txt`). Required. */
    Range: 'bytes=1-3', /*Optional*/
    onProgress: function (progressData) {
        console.log(JSON.stringify(progressData));
    }
}, function(err, data) {
    console.log(err || data.Body);
});

cos.getObject({
    Bucket: 'examplebucket-1250000000', /* Required */
    Region: 'COS_REGION',     /* Bucket region. Required */
    Key: 'exampleobject', /* Required */
    DataType: 'blob',        /* Optional */
    onProgress: function (progressData) {
        console.log(JSON.stringify(progressData));
    }
}, function(err, data) {
    console.log(err || data.Body);
});

cos.getObject({
    Bucket: 'examplebucket-1250000000', /* Your bucket name. Required. */
    Region: 'COS_REGION',  /* Bucket region (required), such as ap-beijing */
    Key: '1.jpg',  /* Object key stored in the bucket (such as `1.jpg` and `a/b/test.txt`). Required. */
    Headers: {
      'x-cos-traffic-limit': 819200, // The speed range is 819200 to 838860800, that is 100 KB/s to 100 MB/s. If the value is not within this range, 400 will be returned.
    },
    onProgress: function (progressData) {
        console.log(JSON.stringify(progressData));
    }
}, function(err, data) {
    console.log(err || data.Body);
});

function(err, data) { ... }


var getObjects = function (marker) {
    cos.getBucket({
        Bucket: config.Bucket,
        Region: config.Region,
        Prefix: 'abc', /* A directory/prefix to download */
        Marker:       marker,
        MaxKeys: 1000,
    }, function (listError, listResult) {
        if (listError) return console.log('list error:', listError);
        var nextMarker = listResult.NextMarker;
        listResult.Contents.forEach(function (item) {
            cos.getObjectUrl({
              Bucket: config.Bucket,
              Region: config.Region,
              Key: item.Key,
            }, function(err, data) {
              if (err) return console.log(err);
              setTimeout(() => {
                var downloadUrl = data.Url + (data.Url.indexOf('?') > -1 ? '&' : '?') + 'response-content-disposition=attachment'; // Add the parameter for a forced download
                window.open(downloadUrl); // This opens the URL in a new window. If you need to open the URL in the current window, you can use the hidden iframe for download, or use the <a> tag download attribute.
              }, 500);
            });
        });
        // If processing is not finished, continue to query the object list on the next page
        if (listResult.IsTruncated === 'true') getMultipleObjects(nextMarker);
    });
}
getObjects();