writeCSV

gistfile1.js

function writeCSV(columnNames, fileName, query, callback){
  var db = mongojs('mongodb://localhost:27017/test', ['jobs']);
  //array of columnNames
  var columns = [];
  //ensure that columnNames is array
  if (typeof columnNames === 'string') {
    columns.push(columnNames);
  } else if (columnNames.constructor === Array) {
    columns = columnNames;
  } else {
    console.log('columnNames is not a string or an array');
    throw err;
  }
  //ensure query is object
  if (typeof query !== 'object') {
    query = {};
  }
  //create write stream
  var file = fs.createWriteStream(fileName + '.csv');
  //write headers
  file.write(columns.join());
  file.write('\n')
  //create cursor
  var cursor = db.jobs.find(query);
  //listen for each document
  cursor.on('data', function(doc){
    //write fields for each document
    columns.forEach(function(columnName, index, arr){
      var field = '' + doc[columnName];
      file.write(field);
      //prevents trailing comma
      if(index !== (arr.length - 1)) {
        file.write(',');
      }
    })
    //start new line
    file.write('\n');
  })
  //functions to call when cursor is finished
  cursor.on('end', function(){
    //end write stream
    file.end()
    //close database
    db.close();
    //optional callback()
    typeof callback === 'function' && callback();
  })
}