node.js – how to write an array to file

If it’s a huuge array and it would take too much memory to serialize it to a string before writing, you can use streams:

var fs = require('fs');

var file = fs.createWriteStream('array.txt');
file.on('error', function(err) { /* error handling */ });
arr.forEach(function(v) { file.write(v.join(', ') + '\n'); });
file.end();