# json-2-csv **Convert JSON to CSV _or_ CSV to JSON** [![NPM version](https://img.shields.io/npm/v/json-2-csv.svg)](https://www.npmjs.org/package/json-2-csv) [![Typings](https://img.shields.io/npm/types/json-2-csv)](https://www.npmjs.org/package/json-2-csv) [![Downloads](https://img.shields.io/npm/dm/json-2-csv.svg)](https://www.npmjs.org/package/json-2-csv) [![Minzipped Size](https://img.shields.io/bundlephobia/minzip/json-2-csv)](https://bundlephobia.com/result?p=json-2-csv) [![Build Status](https://img.shields.io/github/actions/workflow/status/mrodrig/json-2-csv/automated-tests-workflow.yml)](https://github.com/mrodrig/json-2-csv/actions/workflows/automated-tests-workflow.yml) [![Coverage Status](https://coveralls.io/repos/github/mrodrig/json-2-csv/badge.svg?branch=main)](https://coveralls.io/github/mrodrig/json-2-csv?branch=main) [![Maintainability](https://api.codeclimate.com/v1/badges/8c0cc3699d054fb77abe/maintainability)](https://codeclimate.com/github/mrodrig/json-2-csv/maintainability) 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. ## Installation ```bash $ npm install json-2-csv ``` CLI: ```bash $ npm install @mrodrig/json-2-csv-cli ``` ## Upgrading? Upgrading to v5 from v4? Check out the [upgrade guide](https://github.com/mrodrig/json-2-csv/blob/master/upgrade_guides/UPGRADE_4_to_5.md). ## Usage ```javascript let converter = require('json-2-csv'); const csv = await converter.json2csv(data, options); ``` or ```javascript import { json2csv } from 'json-2-csv'; ``` ### API #### `json2csv(array, options)` => `string` Returns the CSV `string` or rejects with an `Error` if there was an issue. * `array` - An array of JSON documents to be converted to CSV. * `options` - (Optional) A JSON document specifying any of the following key value pairs: * `arrayIndexesAsKeys` - Boolean - Should array indexes be included in the generated keys? * Default: `false` * Note: This provides a more accurate representation of the JSON in the returned CSV, but may be less human readable. See [#207](https://github.com/mrodrig/json-2-csv/issues/207) for more details. * `checkSchemaDifferences` - Boolean - Should all documents have the same schema? * Default: `false` * Note: An error will be thrown if some documents have differing schemas when this is set to `true`. * `delimiter` - Document - Specifies the different types of delimiters * `field` - String - Field Delimiter. * Default: `,` * `wrap` - String - Wrap values in the delimiter of choice (e.g. wrap values in quotes). * Default: `"` * `eol` - String - End of Line Delimiter. * Default: `\n` * `emptyFieldValue` - Any - Value that, if specified, will be substituted in for field values that are `undefined`, `null`, or an empty string. * Default: none * `escapeHeaderNestedDots` - Boolean - Should nested dots in header keys be escaped? * Default: `true` * Example: ```json [ { "a.a": "1" } ] ``` * `true` will generate the following CSV: ```csv a\.a 1 ``` * `false` will generate the following CSV: ```csv a.a 1 ``` * Note: This may result in CSV output that does not map back exactly to the original JSON. * `excelBOM` - Boolean - Should a unicode character be prepended to allow Excel to open a UTF-8 encoded file with non-ASCII characters present. * `excludeKeys` - Array - Specify the `string` keys or `RegExp` patterns that should be excluded from the output. Provided `string` keys will also be used as a RegExp to help exclude keys under a specified prefix, such as all keys of Objects in an Array when `expandArrayObjects` is `true` (e.g., providing `'baz'` will exclude `'baz.a'` too). * Default: `[]` * Note: When used with `unwindArrays`, arrays present at excluded key paths will not be unwound. * `expandNestedObjects` - Boolean - Should nested objects be deep-converted to CSV? * Default: `true` * Example: ```json [ { "make": "Nissan", "model": "Murano", "year": 2013, "specifications": { "mileage": 7106, "trim": "S AWD" } } ] ``` * `true` uses the following keys: * `['make', 'model', 'year', 'specifications.mileage', 'specifications.trim']` * `false` uses the following keys: * `['make', 'model', 'year', 'specifications']` * Note: This may result in CSV output that does not map back exactly to the original JSON. * `expandArrayObjects` - Boolean - Should objects in array values be deep-converted to CSV? * Default: `false` * Example: ```json [ { "specifications": [ { "features": [...] }, { "mileage": "5000" } ] } ] ``` * `true` uses the following keys: * `['specifications.features', 'specifications.mileage']` * `false` uses the following keys: * `['specifications']` * Note: This may result in CSV output that does not map back exactly to the original JSON. See #102 for more information. * `keys` - Array - Specify the keys that should be converted. * Default: These will be auto-detected from your data by default. * Keys can either be specified as a String representing the key path that should be converted, or as an Object of the following format: ```javascript { "field": "string", // required "title": "string", // optional "wildcardMatch": false, // optional - default: false } ``` * When specifying keys as an Object, the `field` property specifies the key path, while `title` specifies a more human readable field heading. Additionally, the `wildcardMatch` option allows you to optionally specify that all auto-detected fields with the specified field prefix should be included in the CSV. The list specified can contain a combination of Objects and Strings. * Examples: * `[ 'key1', 'key2', ... ]` * `[ 'key1', { field: 'key2', wildcardMatch: true }]` * `[ { field: 'key1', title: 'Key 1' }, { field: 'key2' }, 'key3', ... ]` * Key Paths - If you are converting a nested object (ie. {info : {name: 'Mike'}}), then set this to ['info.name'] * `parseValue` - Function - Specify how values should be converted into CSV format. This function is provided a single field value at a time and must return a `String`. The built-in parsing method is provided as the second argument for cases where default parsing is preferred. * Default: A built-in method is used to parse out a variety of different value types to well-known formats. * Note: Using this option may override other options, including `useDateIso8601Format` and `useLocaleFormat`. * `prependHeader` - Boolean - Should the auto-generated header be prepended as the first line in the CSV? * Default: `true` * `sortHeader` - Boolean or Function - Should the header keys be sorted in alphabetical order? or pass a function to use a custom sorting function * Default: `false` * `trimFieldValues` - Boolean - Should the field values be trimmed? * Default: `false` * `trimHeaderFields` - Boolean - Should the header fields be trimmed? * Default: `false` * `unwindArrays` - Boolean - Should array values be "unwound" such that there is one line per value in the array? * Default: `false` * Example: ```json [ { "_id": {"$oid": "5cf7ca3616c91100018844af"}, "data": {"category": "Computers", "options": [{"name": "MacBook Pro 15"}, {"name": "MacBook Air 13"}]} }, { "_id": {"$oid": "5cf7ca3616c91100018844bf"}, "data": {"category": "Cars", "options": [{"name": "Supercharger"}, {"name": "Turbocharger"}]} } ] ``` * `true` will unwind the JSON to four objects, and therefore four lines of CSV values: ```csv _id.$oid,data.category,data.options.name 5cf7ca3616c91100018844af,Computers,MacBook Pro 15 5cf7ca3616c91100018844af,Computers,MacBook Air 13 5cf7ca3616c91100018844bf,Cars,Supercharger 5cf7ca3616c91100018844bf,Cars,Turbocharger ``` * `false` will leave the values unwound and will convert the array as-is (when this option is used without expandArrayObjects): ```csv _id.$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: `,` * `wrap` - String - The character that field values are wrapped in. * Default: `"` * `eol` - String - End of Line Delimiter. * Default: `\n` * `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` * `trimFieldValues` - Boolean - Should the field values be trimmed? * Default: `false` ### CLI 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: ```bash $ npm install @mrodrig/json-2-csv-cli ``` #### json2csv ``` Usage: json2csv [options] Options: -V, --version output the version number -o, --output [output] Path of output file. If not provided, then stdout will be used -f, --field Optional field delimiter -w, --wrap Optional wrap delimiter -e, --eol Optional end of line delimiter -b, --excel-bom Excel Byte Order Mark character prepended to CSV -W, --without-header Withhold the prepended header -s, --sort-header Sort the header fields -H, --trim-header Trim header fields -F, --trim-fields Trim field values -S, --check-schema Check for schema differences -E, --empty-field-value Empty field value -A, --expand-array-objects Expand array objects -k, --keys [keys] Keys of documents to convert to CSV -h, --help output usage information ``` #### csv2json ``` Usage: csv2json [options] Options: -V, --version output the version number -c, --csv Path of json file to be converted -o, --output [output] Path of output file. If not provided, then stdout will be used -f, --field Optional field delimiter -w, --wrap Optional wrap delimiter -e, --eol Optional end of line delimiter -b, --excel-bom Excel Byte Order Mark character prepended to CSV -H, --trim-header Trim header fields -F, --trim-fields Trim field values -k, --keys [keys] Keys of documents to convert to CSV -h, --help output usage information ``` ## Tests ```bash $ npm test ``` To see test coverage, please run: ```bash $ 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` * *and* * `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](https://github.com/GabrielCastro)! * Synchronous use case support (as of 5.0.0) - thanks to [@Nokel81](https://github.com/Nokel81)

	Stars	Issues	Version	Updated	Created
csv	3,867	43	6.3.9	4 days ago	13 years ago
csv-generate	3,866	43	4.4.1	4 days ago	10 years ago
fast-csv	1,586	48	5.0.1	3 months ago	12 years ago
json-2-csv	388	3	5.5.1	2 months ago	10 years ago
papaparse	12,188	196	5.4.1	a year ago	9 years ago

csv vs csv-generate vs fast-csv vs json-2-csv vs papaparse

Downloads in past1 Month3 Months6 Months1 Year2 Years5 YearsAll time

Stats

Popular Searches

Sick of boring JavaScript newsletters?

Downloads in past