<a id="download" ng-click="downloadfile()">Download FileName</a>

$scope.downloadfile=function(){
var download = document.getElementById("download");
$scope.downloadData =  锟斤拷锟斤拷JFIF,,锟斤拷xPhotoshop 3.08BIMgP53616c7465645f5fdfdda5a4f94df34e8d1d8e056e7e5dcc820ce57f793e13bfa39119fdc1b0c079锟斤拷C锟斤拷�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟�锟;

download.onclick = function() {

  downloadFile("text.jpg", $scope.downloadData);
}

function downloadFile(filename, text) {
  var pom = document.createElement('a');
  pom.setAttribute('href', 'data:image/jpeg;charset-utf-8,' + encodeURIComponent(text));
  pom.setAttribute('download', filename);
  pom.click();
}
}