get gist file with $.ajax

getGistFile.js

function getGistFile (gist, filename, cb) {
  $.ajax({
    url: 'https://api.github.com/gists/' + gist,
    type: 'GET',
    dataType: 'jsonp'
  }).success( function(gistdata) {
    var content = gistdata.data.files[filename].content;
    cb(null, JSON.parse(content))
  }).error( function(e) {
    cb(e)
  });
}