How can I parse records on demand with Node.js?

Question

Is there a Node module that can parse a specific number of records from a CSV file? The use case is to parse a large log file and deliver records to a paging client as requested.

node-csv can't yet do this, and the closest I've found is to read lines one by one, which requires reinventing the CSV parsing wheel, and will break on multi-line records.

But let's lower the bar: how can I parse single-line CSV records one by one with Node.js? Pretty trivial task in most other languages.

Answer 1

As far as I understand, you just want to parse the comma-separated line of values into an array? If so, try this one:

https://npmjs.org/package/csvrow

Answer 2

Parsing a single 'line' (which can also have embedded newlines):

var csv = require('csv'); // node-csv

csv()
  .from.string(SINGLE_LINE_OF_CSV)
  .to.array(function(record) {
    console.log('R', record);
  });

I'm not sure what you mean by 'a specific number of records from a CSV file', or what the issue is exactly. Once you've read the amount you need, just send the response back to the client and you're done.

EDIT: if you want to implement paging, you can use node-csv too:

var csv   = require('csv');
var skip  = 100;
var limit = 10;

csv()
  .from.path('file.csv')
  .on('record', function(row, index) {
    if (index >= skip && index < (skip + limit))
      console.log('R', index);
  });