This node module will convert an array of JSON documents to a CSV string. Column headings will be automatically generated based on the keys of the JSON documents. Nested documents will have a '.' appended between the keys.

It is also capable of converting CSV of the same form back into the original array of JSON documents. The columns headings will be used as the JSON document keys. All lines must have the same exact number of CSV values.

$ npm install json-2-csv

$ npm install @mrodrig/json-2-csv-cli

Upgrading to v5 from v4? Check out the upgrade guide .

let converter = require('json-2-csv');
const csv = await converter.json2csv(data, options);

import { json2csv } from 'json-2-csv';

Returns the CSV string or rejects with an Error if there was an issue.

_id.$oid,data.category,data.options.name
5cf7ca3616c91100018844af,Computers,MacBook Pro 15
5cf7ca3616c91100018844af,Computers,MacBook Air 13
5cf7ca3616c91100018844bf,Cars,Supercharger
5cf7ca3616c91100018844bf,Cars,Turbocharger
false will leave the values unwound and will convert the array as-is (when this option is used without expandArrayObjects):
_id.$oid,data.category,data.options
5cf7ca3616c91100018844af,Computers,"[{""name"":""MacBook Pro 15""},{""name"":""MacBook Air 13""}]"
5cf7ca3616c91100018844bf,Cars,"[{""name"":""Supercharger""},{""name"":""Turbocharger""}]"
Note: This may result in CSV output that does not map back exactly to the original JSON.
useDateIso8601Format - Boolean - Should date values be converted to an ISO8601 date string?
Default: false
Note: If selected, values will be converted using toISOString() rather than toString() or toLocaleString() depending on the other options provided.
useLocaleFormat - Boolean - Should values be converted to a locale specific string?
Default: false
Note: If selected, values will be converted using toLocaleString() rather than toString()
wrapBooleans - Boolean - Should boolean values be wrapped in wrap delimiters to prevent Excel from converting them to Excel's TRUE/FALSE Boolean values.
Default: false
preventCsvInjection - Boolean - Should CSV injection be prevented by left trimming these characters: Equals (=), Plus (+), Minus (-), At (@), Tab (0x09), Carriage return (0x0D).
Default: false
csv2json(csv, options) => object[]
Returns the JSON object array (object[]) or rejects with an Error if there was an issue.
csv - A string of CSV
options - (Optional) A JSON document specifying any of the following key value pairs:
delimiter - Document - Specifies the different types of delimiters
field - String - Field Delimiter.
Default: ,
excelBOM - Boolean - Does the CSV contain a unicode character prepended in order to allow Excel to open a UTF-8 encoded file with non-ASCII characters present?
Default: false
headerFields - Array - Specify the field names (as strings) in place of a header line in the CSV itself.
Default: Parses the header fields directly from the CSV string
If you want to generate a nested object (ie. {info : {name: 'Mike'}}), then use . characters in the string to denote a nested field, like ['info.name']
If your CSV has a header line included, then don't specify the option to utilize the default values that will be parsed from the CSV.
keys - Array - Specify the keys (as strings) that should be converted.
Default: null
If you have a nested object (ie. {info : {name: 'Mike'}}), then set this to ['info.name']
If you want all keys to be converted, then specify null or don't specify the option to utilize the default.
parseValue - Function - Specify how String representations of field values should be parsed when converting back to JSON. This function is provided a single String and can return any value.
Default: JSON.parse - An attempt is made to convert the String back to its original value using JSON.parse.
trimHeaderFields - Boolean - Should the header fields be trimmed?
Default: false
Note: As of 3.5.8, the command line interface functionality has been pulled out to a separate package. Please be sure to
install the @mrodrig/json-2-csv-cli NPM package if you wish to use the CLI functionality shown below:
$ npm install @mrodrig/json-2-csv-cli
json2csv

Usage: json2csv <jsonFile> [options]
Arguments:
  jsonFile                         JSON file to convert
Options:
  -V, --version                    output the version number
  -o, --output [output]            Path of output file. If not provided, then stdout will be used
  -a, --array-indexes-as-keys      Includes array indexes in the generated keys
  -S, --check-schema               Check for schema differences
  -f, --field <delimiter>          Field delimiter
  -w, --wrap <delimiter>           Wrap delimiter
  -e, --eol <delimiter>            End of Line delimiter
  -E, --empty-field-value <value>  Empty field value
  -n, --expand-nested-objects      Expand nested objects to be deep converted to CSV
  -k, --keys [keys]                Keys of documents to convert to CSV
  -d, --escape-header-nested-dots  Escape header nested dots
  -b, --excel-bom                  Excel Byte Order Mark character prepended to CSV
  -x, --exclude-keys [keys]        Comma separated list of keys to exclude
  -A, --expand-array-objects       Expand array objects
  -W, --without-header             Withhold the prepended header
  -p, --prevent-csv-injection      Prevent CSV Injection
  -s, --sort-header                Sort the header fields
  -F, --trim-fields                Trim field values
  -H, --trim-header                Trim header fields
  -U, --unwind-arrays              Unwind array values to their own CSV line
  -I, --iso-date-format            Use ISO 8601 date format
  -L, --locale-format              Use locale format for values
  -B, --wrap-booleans              Wrap booleans
  -h, --help                       display help for command
csv2json

Usage: csv2json <csvFile> [options]
Arguments:
  csvFile                      CSV file to convert
Options:
  -V, --version                output the version number
  -o, --output [output]        Path of output file. If not provided, then stdout will be used
  -f, --field <delimiter>      Field delimiter
  -w, --wrap <delimiter>       Wrap delimiter
  -e, --eol <delimiter>        End of Line delimiter
  -b, --excel-bom              Excel Byte Order Mark character prepended to CSV
  -p, --prevent-csv-injection  Prevent CSV Injection
  -F, --trim-fields            Trim field values
  -H, --trim-header            Trim header fields
  -h, --header-fields          Specify the fields names in place a header line in the CSV itself
  -k, --keys [keys]            Keys of documents to convert to CSV
  --help                       display help for command
Tests

$ npm test
To see test coverage, please run:
$ npm run coverage
Features

Header Generation (per document keys)
Allows for conversion of specific keys in both json2csv and csv2json via the options.keys parameter (as of 1.1.2)
Document schema verification functionality (field order is irrelevant) (as of 1.1.0)
Supports sub-documents natively
Supports arrays as document values for both json2csv and csv2json
Custom ordering of columns (see F.A.Q. for more information)
Ability to re-generate the JSON documents that were used to generate the CSV (including nested documents)
Allows for custom field delimiters, end of line delimiters, etc.
Wrapped value support for json2csv and csv2json (as of 1.3.0)
Support for multiple different schemas (as of 1.4.0)
RFC 4180 Compliance (as of 3.0.0)
CLI functionality (as of 3.0.0)
csv2json test.csv -o output.json
json2csv test.json -o output.csv -W -k arrayOfStrings -o output.csv
Empty field value option (as of 3.1.0)
TypeScript typings included (as of 3.4.0) - thanks to @GabrielCastro!
Synchronous use case support (as of 5.0.0) - thanks to @Nokel81