json2csv

What is json2csv?

The json2csv npm package is a powerful tool for converting JSON data to CSV format. It is widely used for data transformation and export tasks, making it easier to handle JSON data in a tabular format.

What are json2csv's main functionalities?

Convert JSON to CSV

This feature allows you to convert a JSON array into a CSV string. The code sample demonstrates how to use the `parse` function from the json2csv package to transform a JSON array into CSV format.

const { parse } = require('json2csv');
const json = [{ "name": "John", "age": 30 }, { "name": "Jane", "age": 25 }];
const csv = parse(json);
console.log(csv);

Customizing CSV Fields

This feature allows you to specify which fields to include in the CSV output. The code sample shows how to define a list of fields and pass them as options to the `parse` function.

const { parse } = require('json2csv');
const json = [{ "name": "John", "age": 30 }, { "name": "Jane", "age": 25 }];
const fields = ['name', 'age'];
const opts = { fields };
const csv = parse(json, opts);
console.log(csv);

Handling Nested JSON Objects

This feature allows you to handle nested JSON objects and flatten them into CSV format. The code sample demonstrates how to specify nested fields in the options to correctly map them to CSV columns.

const { parse } = require('json2csv');
const json = [{ "name": "John", "address": { "city": "New York", "state": "NY" } }, { "name": "Jane", "address": { "city": "San Francisco", "state": "CA" } }];
const fields = ['name', 'address.city', 'address.state'];
const opts = { fields };
const csv = parse(json, opts);
console.log(csv);

Other packages similar to json2csv

csv-writer

The csv-writer package provides a simple and flexible way to write CSV files. It supports writing both objects and arrays to CSV, and allows for customization of headers and field delimiters. Compared to json2csv, csv-writer focuses more on writing CSV files rather than converting JSON to CSV strings.

fast-csv

The fast-csv package is a comprehensive library for parsing and formatting CSV files. It offers high performance and a wide range of features, including support for streaming and handling large datasets. While json2csv is primarily focused on converting JSON to CSV, fast-csv provides more extensive functionality for working with CSV data in general.

papaparse

The papaparse package is a powerful CSV parser that can handle large files and supports various configurations for parsing and formatting. It is known for its speed and reliability. Unlike json2csv, which is mainly used for converting JSON to CSV, papaparse excels at parsing CSV files into JSON and other formats.

README

json2csv

Converts json into csv with column titles and proper line endings. Can be used as a module and from the command line.

How to use

Install

$ npm install json2csv --save

Include the module and run

var json2csv = require('json2csv');
var fields = ['field1', 'field2', 'field3'];

json2csv({ data: myData, fields: fields }, function(err, csv) {
  if (err) console.log(err);
  console.log(csv);
});

Features

• Uses proper line endings on various operating systems
• Handles double quotes
• Allows custom column selection
• Reads column selection from file
• Pretty writing to stdout
• Supports optional custom delimiters
• Supports optional custom eol value
• Not create CSV column title by passing hasCSVColumnTitle: false, into params.
• If field is not exist in object then the field value in CSV will be empty.

Use as a module

Example 1

var json2csv = require('json2csv');
var fields = ['car', 'price', 'color'];
var myCars = [
  {
    "car": "Audi",
    "price": 40000,
    "color": "blue"
  }, {
    "car": "BMW",
    "price": 35000,
    "color": "black"
  }, {
    "car": "Porsche",
    "price": 60000,
    "color": "green"
  }
];

json2csv({ data: myCars, fields: fields }, function(err, csv) {
  if (err) console.log(err);
  fs.writeFile('file.csv', csv, function(err) {
    if (err) throw err;
    console.log('file saved');
  });
});

The content of the "file.csv" should be

car, price, color
"Audi", 40000, "blue"
"BMW", 35000, "black"
"Porsche", 60000, "green"

Example 2

Similarly to mongoexport you can choose which fields to export

var json2csv = require('json2csv');
var fields = ['car', 'color'];

json2csv({ data: myCars, fields: fields }, function(err, csv) {
  if (err) console.log(err);
  console.log(csv);
});

Results in

car, color
"Audi", "blue"
"BMW", "black"
"Porsche", "green"

Example 3

Use a custom delimiter to create tsv files. Add it as the value of the del property on the parameters:

var json2csv = require('json2csv');
var fields = ['car', 'price', 'color'];

json2csv({ data: myCars, fields: fields, del: '\t' }, function(err, tsv) {
  if (err) console.log(err);
  console.log(tsv);
});

Will output:

car price color
"Audi"  10000 "blue"
"BMW" 15000 "red"
"Mercedes"  20000 "yellow"
"Porsche" 30000 "green"

If no delimiter is specified, the default , is used

Example 4

You can choose custom column names for the exported file.

var json2csv = require('json2csv');
var fields = ['car', 'price'];
var fieldNames = ['Car Name', 'Price USD'];

json2csv({ data: myCars, fields: fields, fieldNames: fieldNames }, function(err, csv) {
  if (err) console.log(err);
  console.log(csv);
});

Results in

"Car Name", "Price USD"
"Audi", 10000
"BMW", 15000
"Porsche", 30000

Command Line Interface

json2csv can also be called from the command line

Usage: json2csv.js [options]

Options:

  -h, --help                   output usage information
  -V, --version                output the version number
  -i, --input <input>          Path and name of the incoming json file.
  -o, --output [output]        Path and name of the resulting csv file. Defaults to console.
  -f, --fields <fields>        Specify the fields to convert.
  -l, --fieldList [list]       Specify a file with a list of fields to include. One field per line.
  -d, --delimiter [delimiter]  Specify a delimiter other than the default comma to use.
  -e, --eol [value]            Specify an EOL value after each row.
  -n, --no-header              Disable the column name header
  -p, --pretty                 Use only when printing to console. Logs output in pretty tables.

An input file -i and fields -f are required. If no output -o is specified the result is logged to the console. Use -p to show the result in a beautiful table inside the console.

CLI examples

Input file and specify fields

$ json2csv -i input.json -f carModel,price,color

carModel,price,color
"Audi",10000,"blue"
"BMW",15000,"red"
"Mercedes",20000,"yellow"
"Porsche",30000,"green"

Input file, specify fields and use pretty logging

$ json2csv -i input.json -f carModel,price,color -p

Input file, specify fields and write to file

$ json2csv -i input.json -f carModel,price,color -o out.csv

Content of out.csv is

carModel,price,color
"Audi",10000,"blue"
"BMW",15000,"red"
"Mercedes",20000,"yellow"
"Porsche",30000,"green"

Input file, use field list and write to file

The file fieldList contains

carModel
price
color

Use the following command with the -l flag

$ json2csv -i input.json -l fieldList -o out.csv

Content of out.csv is

carModel,price,color
"Audi",10000,"blue"
"BMW",15000,"red"
"Mercedes",20000,"yellow"
"Porsche",30000,"green"

Read from stdin

$ json2csv -f price
[{"price":1000},{"price":2000}]

Hit Enter and afterwards CTRL + D to end reading from stdin. The terminal should show

price
1000
2000

Testing

Requires mocha, should and async.

Run

$ npm test

Formatting json2csv

Requires js-beautify.

Run

$ npm run format

Contributors

Install require packages for development run following command under json2csv dir.

Run

$ npm install

Could you please make sure code is formatted and test passed before submit Pull Requests?

See Testing and Formatting json2csv above.

But I want streams!

Check out my other module json2csv-stream. It transforms an incoming stream containing json data into an outgoing csv stream.

License

Copyright (C) 2012 [Mirco Zeiss](mailto: [e-mail])

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.