csv-write-stream

A CSV encoder stream that produces properly escaped CSVs.

A through stream. Write arrays of strings (or JS objects) and you will receive a properly escaped CSV stream out the other end.

usage

var writer = csvWriter([options])

var csvWriter = require('csv-write-stream')
var writer = csvWriter()

writer is a duplex stream -- you can pipe data to it and it will emit a string for each line of the CSV

default options

{
  separator: ',',
  newline: '\n',
  headers: undefined,
  sendHeaders: true
}

headers can be an array of strings to use as the header row. if you don't specify a header row the keys of the first row written to the stream will be used as the header row IF the first row is an object (see the test suite for more details). if the sendHeaders option is set to false, the headers will be used for ordering the data but will never be written to the stream.

headers can also be an array of objects containing a header title, field and default. The title will replace the field in header. The field defines the object key. The default set the default value if a key is not found in a given row.

example of auto headers:

var writer = csvWriter()
writer.pipe(fs.createWriteStream('out.csv'))
writer.write({hello: "world", foo: "bar", baz: "taco"})
writer.end()

// produces: hello,foo,baz\nworld,bar,taco\n

example of specifying headers:

var writer = csvWriter({ headers: ["hello", "foo"]})
writer.pipe(fs.createWriteStream('out.csv'))
writer.write(['world', 'bar'])
writer.end()

// produces: hello,foo\nworld,bar\n

example of not sending headers:

var writer = csvWriter({sendHeaders: false})
writer.pipe(fs.createWriteStream('out.csv'))
writer.write({hello: "world", foo: "bar", baz: "taco"})
writer.end()

// produces: world,bar,taco\n

example of with headers objects (title, field and defaults): note: header objects does not work in the cli.

var headers = [
  { title: 'SSN', field: 'ssn_value', default: 'NA'},
  { title: 'First Name', field: 'fName', default: ''},
  { title: 'Last Name', field: 'lName', default: ''}
]
var writer = csvWriter({ headers: headers })
writer.pipe(fs.createWriteStream('out.csv'))
writer.write({ fName: 'Joe', lName: 'Dirt', ssn_value: '111-22-3333'})
writer.end()

// produces:
// SSN,First Name,Last Name\n
// 000-11-0000,Joe,Dirt\n

see the test suite for more examples

run the test suite

$ npm install
$ npm test

cli usage

This module also includes a CLI, which you can pipe ndjson to stdin and it will print csv on stdout. You can install it with npm install -g csv-write-stream.

$ csv-write --help
usage: csv-write [-h] [-v] [--separator SEPARATOR] [--newline NEWLINE]
                 [--headers HEADERS [HEADERS ...]] [--no-send-headers]


A CSV encoder stream that produces properly escaped CSVs. JSON is read from
STDIN, formatted to CSV, and written to STDOUT.

Optional arguments:
  -h, --help            Show this help message and exit.
  -v, --version         Show program's version number and exit.
  --separator SEPARATOR
                        The separator character to use. Defaults to ','.
  --newline NEWLINE     The newline character to use. Defaults to $'\n'.
  --headers HEADERS [HEADERS ...]
                        The list of headers to use. If omitted, the keys of
                        the first row written to STDIN will be used
  --no-send-headers     Don't print the header row.

$ cat example.ndjson | csv-write > example.csv