csv

Parsing CSV

This feature allows you to parse CSV data into arrays or objects. The code sample demonstrates how to parse a simple CSV string.

"use strict";
const parse = require('csv-parse');
const assert = require('assert');

const input = 'a,b,c\nd,e,f';
parse(input, function(err, output){
  assert.deepEqual(
    output,
    [['a', 'b', 'c'], ['d', 'e', 'f']]
  );
});

Stringifying CSV

This feature allows you to convert arrays or objects into CSV strings. The code sample shows how to stringify an array of arrays into a CSV string.

"use strict";
const stringify = require('csv-stringify');
const assert = require('assert');

const input = [['a', 'b', 'c'], ['d', 'e', 'f']];
stringify(input, function(err, output){
  assert.equal(
    output,
    'a,b,c\nd,e,f\n'
  );
});

Transforming Data

This feature allows you to apply a transformation to the CSV data. The code sample demonstrates how to convert all the values in the CSV to uppercase.

"use strict";
const transform = require('stream-transform');
const assert = require('assert');

const input = [['a', 'b', 'c'], ['d', 'e', 'f']];
const transformer = transform(function(record, callback){
  callback(null, record.map(value => value.toUpperCase()));
});

transformer.write(input[0]);
transformer.write(input[1]);
transformer.end();

const output = [];
transformer.on('readable', function(){
  let row;
  while ((row = transformer.read()) !== null) {
    output.push(row);
  }
});

transformer.on('end', function(){
  assert.deepEqual(
    output,
    [['A', 'B', 'C'], ['D', 'E', 'F']]
  );
});

Streaming API

This feature provides a streaming API for working with large CSV files without loading the entire file into memory. The code sample demonstrates how to read a CSV file as a stream and parse it.

"use strict";
const fs = require('fs');
const parse = require('csv-parse');

const parser = parse({columns: true});
const input = fs.createReadStream('/path/to/input.csv');

input.pipe(parser);

parser.on('readable', function(){
  let record;
  while ((record = parser.read()) !== null) {
    // Work with each record
  }
});

parser.on('end', function(){
  // Handle end of parsing
});