How to read a file line by line into an array in node.js [duplicate]

Question

I need to be able to read a simple text file that contains a series of numbers for each line.

These numbers need to be read and stored somewhere in my code so I figure an array is the best way to go. Once the array has the values stored I can use it for further manipulation but I can't seem to actually read and push values into my array from each line in a text file.

What's the best way to do this? All help is appreciated! Thanks!

Cheers stackoverflow.com/questions/6831918/…

Hasan Huseyin Ozkaya
– Hasan Huseyin Ozkaya

2017-07-20 08:15:39 +00:00
Commented Jul 20, 2017 at 8:15 — Hasan Huseyin Ozkaya
– Hasan Huseyin Ozkaya, Commented Jul 20, 2017 at 8:15
response.split("\n")

Jonas Wilms
– Jonas Wilms

2017-07-20 08:23:28 +00:00
Commented Jul 20, 2017 at 8:23 — Jonas Wilms
– Jonas Wilms, Commented Jul 20, 2017 at 8:23

kmsheng · Accepted Answer · 2017-07-20 08:24:40Z

13

var fs = require('fs');
var readline = require('readline');
var stream = require('stream');

var instream = fs.createReadStream('./test.txt');
var outstream = new stream;
var rl = readline.createInterface(instream, outstream);

var arr = [];

rl.on('line', function(line) {
  // process line here
  arr.push(line);
});

rl.on('close', function() {
  // do something on finish here
  console.log('arr', arr);
});

This approach also handles large text file. https://coderwall.com/p/ohjerg/read-large-text-files-in-nodejs

answered Jul 20, 2017 at 8:24

kmsheng

1621 silver badge6 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Dianne Over a year ago

Is there anyway to return the array instead of logging it ot the console (in the case where the above code was inside of a function)?

b-m-f · Accepted Answer · 2017-07-20 08:14:13Z

2

Check out this answer.

This is the solution proposed there:

var lineReader = require('readline').createInterface({
  input: require('fs').createReadStream('file.in')
});

lineReader.on('line', function (line) {
  console.log('Line from file:', line);
});

Has also been added to the Node docs.

answered Jul 20, 2017 at 8:14

b-m-f

1,3382 gold badges13 silver badges30 bronze badges

Collectives™ on Stack Overflow

How to read a file line by line into an array in node.js [duplicate]

2 Answers 2

1 Comment

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Linked

Related