Express App Only Display JSON on Windows, Not Debian or Heroku

user_12772020 0
Viewed 41

I have created an express app which successfully displays JSON on Windows - I have had no problem on Firefox or Chrome. However, when I try to run the same code on my linux setup (Debian) or deploy it on Heroku, receives an empty array: []. How can I get it to display on more than just windows? Here is the js file:

var express = require('express');
var router = express.Router();
var fs = require('fs');

//read file of chore todos
function readCSV(callback) {
  fs.readFile('./data/todoList.csv', function(err, data) {
    if(err) throw err;
    var dataStr = data.toString();
    var array = dataStr.split("\n");
    fs.writeFileSync('./data/todo.json', JSON.stringify(convertToJSON(array), null, 4));
    var temp = convertToJSON(array);
    return callback(temp);
  });
}

//convert array to JSON
function convertToJSON(array) {
  var rows = array.toString();
  rows = rows.split("\r");
  for (var i=1; i<rows.length;i++) {
    rows[i] = rows[i].replace(rows[i][0], "");
  }
  var asJSON = [];
  // get column headers
  var headers = rows[0].split(",");
  
  for (var i=1; i<rows.length-1; i++) {
    var obj = {}
    var currentRow = rows[i].split(",");

    for (var j=0; j<headers.length; j++) {
      obj[headers[j]] = currentRow[j];
    }
    asJSON.push(obj);
  }
  return asJSON;
}

var returnJSON;
readCSV(function(temp) {
  returnJSON=temp;
})

router.get('/', function (req, res, next) {
  res.json(returnJSON);
});

module.exports = router;
express node.js heroku operating-system javascript
1 Answers

The problem is caused by the below line in convertToJSON() function

rows = rows.split("\r");

Consider the following csv file created in windows.

enter image description here

And its binary representation: enter image description here

You will notice that the newline character is denoted by "\r \n" or CR LF characters

If the same csv is created in Linux, its binary version will look like below: enter image description here Here the newline character is denoted by "\n" or LF character.

Different operating systems handle the newline character differently. Refer https://en.wikipedia.org/wiki/Newline for more details.

To get it working for Linux, you can change to below

rows = rows.split("\n");

However, this will not work for windows.

How can I get it to display on more than just windows?

Use csvtojson to handle the edge cases like these and most of the heavy lifting. However if you want to handle it on your own you can check how the package handles it here

https://github.com/Keyang/node-csvtojson/blob/master/src/getEol.ts

user_34237500
Related