jsonexport

What is jsonexport?

The jsonexport npm package is a utility that allows you to convert JSON data into CSV format. It is particularly useful for exporting data from JSON APIs or databases into a format that can be easily imported into spreadsheet applications like Microsoft Excel or Google Sheets.

What are jsonexport's main functionalities?

Basic JSON to CSV Conversion

This feature allows you to convert a simple JSON array into CSV format. The code sample demonstrates how to convert an array of JSON objects into a CSV string.

const jsonexport = require('jsonexport');
const data = [{"name":"John","age":30},{"name":"Jane","age":25}];
jsonexport(data, function(err, csv){
    if(err) return console.error(err);
    console.log(csv);
});

Nested JSON to CSV Conversion

This feature allows you to convert nested JSON objects into CSV format. The code sample demonstrates how to handle nested JSON structures and convert them into a flat CSV format.

const jsonexport = require('jsonexport');
const data = [{"name":"John","age":30,"address":{"city":"New York","state":"NY"}},{"name":"Jane","age":25,"address":{"city":"San Francisco","state":"CA"}}];
jsonexport(data, function(err, csv){
    if(err) return console.error(err);
    console.log(csv);
});

Custom Delimiters

This feature allows you to specify custom delimiters for the CSV output. The code sample demonstrates how to use a semicolon as the delimiter instead of the default comma.

const jsonexport = require('jsonexport');
const data = [{"name":"John","age":30},{"name":"Jane","age":25}];
const options = {delimiter: ';'};
jsonexport(data, options, function(err, csv){
    if(err) return console.error(err);
    console.log(csv);
});

Other packages similar to jsonexport

json2csv

The json2csv package is another popular library for converting JSON to CSV. It offers similar functionalities to jsonexport, including support for nested JSON objects and custom delimiters. However, json2csv provides more advanced features like field selection, field renaming, and data transformation.

csv-writer

The csv-writer package is a versatile library for writing CSV files. While it does not directly convert JSON to CSV, it allows you to write CSV files from JavaScript objects, making it a good alternative for more complex CSV writing needs. It offers features like custom headers, field transformations, and support for different CSV formats.

README

jsonexport {} → 📄

✔ easy to use 👌 (should work as expected without much customization)️

✔ extendable 🕺 (many options to customize the output)

✔️ tiny 🐜 (0 dependencies)

✔ scalable 💪 (works with big files using Streams)

✔ fast ⚡

Project Page

Online Demo Page

Table of Contents

• Usage
• CLI
• Browser
  • Browser Import Examples
• Stream
• Promise
• JSON Array Example
  • Simple Array
  • JSON Object Example
• Options
  • typeHandlers
• Contributors

Usage

Installation command is npm install jsonexport.

Run tests with npm test.

const jsonexport = require('jsonexport');

jsonexport({lang: 'Node.js', module: 'jsonexport'}, {rowDelimiter: '|'}, function(err, csv){
    if (err) return console.error(err);
    console.log(csv);
});

CLI

Global installation command is npm install -g jsonexport.

Convert JSON to CSV using cat data.json | jsonexport or jsonexport data.json

Usage: jsonexport <JSON filename> <CSV filename>

Browser

Use the code in the folder named dist to run jsonexport in the browser

Browser Import Examples

Webpack

const jsonexport = require("jsonexport/dist")

Typescript

import * as jsonexport from "jsonexport/dist"

Stream

const jsonexport = require('jsonexport');
const fs = require('fs');

const reader = fs.createReadStream('data.json');
const writer = fs.createWriteStream('out.csv');

reader.pipe(jsonexport()).pipe(writer);

Promise

const jsonexport = require('jsonexport')
try {
    const csv = await jsonexport({lang: 'Node.js', module: 'jsonexport'}, {rowDelimiter: '|'});
} catch (err) {
    console.error(err);
}

JSON Array Example

Simple Array

Code

const jsonexport = require('jsonexport');

const contacts = [{
    name: 'Bob',
    lastname: 'Smith'
},{
    name: 'James',
    lastname: 'David'
},{
    name: 'Robert',
    lastname: 'Miller'
},{
    name: 'David',
    lastname: 'Martin'
}];

jsonexport(contacts, function(err, csv){
    if (err) return console.error(err);
    console.log(csv);
});

Result

name,lastname
Bob,Smith
James,David
Robert,Miller
David,Martin

Complex Array

Code

const jsonexport = require('jsonexport');

const contacts = [{
   name: 'Bob',
   lastname: 'Smith',
   family: {
       name: 'Peter',
       type: 'Father'
   }
},{
   name: 'James',
   lastname: 'David',
   family:{
       name: 'Julie',
       type: 'Mother'
   }
},{
   name: 'Robert',
   lastname: 'Miller',
   family: null,
   location: [1231,3214,4214]
},{
   name: 'David',
   lastname: 'Martin',
   nickname: 'dmartin'
}];

jsonexport(contacts, function(err, csv){
    if (err) return console.error(err);
    console.log(csv);
});

Result

name,lastname,family.name,family.type,family,location,nickname
Bob,Smith,Peter,Father
James,David,Julie,Mother
Robert,Miller,,,,1231;3214;4214
David,Martin,,,,,dmartin

JSON Object Example

Simple Object

Code

const jsonexport = require('jsonexport');

const stats = {
    cars: 12,
    roads: 5,
    traffic: 'slow'
};

jsonexport(stats, function(err, csv){
    if(err) return console.error(err);
    console.log(csv);
});

Result

cars,12
roads,5
traffic,slow

Complex Object

Code

const jsonexport = require('jsonexport');

const stats = {
    cars: 12,
    roads: 5,
    traffic: 'slow',
    speed: {
        max: 123,
        avg: 20,
        min: 5
    },
    size: [10,20]
};

jsonexport(stats, function(err, csv){
    if(err) return console.error(err);
    console.log(csv);
});

Result

cars,12
roads,5
traffic,slow
speed.max,123
speed.avg,20
speed.min,5
size,10;20

Options

In order to get the most of out of this module, you can customize many parameters and functions.

• headerPathString - String Used to create the propriety path, defaults to . example contact: {name: 'example} = contact.name
• fillGaps - Boolean Set this option if don't want to have empty cells in case of an object with multiple nested items (array prop), defaults to false Issue #22
• fillTopRow - Boolean try filling top rows first for unpopular colums, defaults to false
• headers - Array Used to set a custom header order, defaults to [] example ['lastname', 'name']
• rename - Array Used to set a custom header text, defaults to [] example ['Last Name', 'Name']
• mapHeaders - Function Post-process headers after they are calculated with delimiters, example mapHeaders: (header) => header.replace(/foo\./, '')
• rowDelimiter - String Change the file row delimiter
  • Defaults to , (cvs format).
  • Use \t for xls format.
  • Use ; for (windows excel .csv format).
• textDelimiter - String The character used to escape the text content if needed (default to ")
• forceTextDelimiter - Boolean Set this option to true to wrap every data item and header in the textDelimiter. Defaults to false
• endOfLine - String Replace the OS default EOL.
• mainPathItem - String Every header will have the mainPathItem as the base.
• arrayPathString - String This is used to output primitive arrays in a single column, defaults to ;
• booleanTrueString - String Will be used instead of true.
• booleanFalseString - String Will be used instead of false.
• includeHeaders - Boolean Set this option to false to hide the CSV headers.
• undefinedString - String If you want to display a custom value for undefined strings, use this option. Defaults to .
• verticalOutput - Boolean Set this option to false to create a horizontal output for JSON Objects, headers in the first row, values in the second.
• typeHandlers - {typeName:(value, index, parent)=>any A key map of constructors used to match by instance to create a value using the defined function (see example)

typeHandlers

Define types by constructors and what function to run when that type is matched

const jsonexport = require('jsonexport');

//data
const contacts = {
  'a' : Buffer.from('a2b', 'utf8'),
  'b' : Buffer.from('other field', 'utf8'),
  'x' : 22,
  'z' : function(){return 'bad ace'}
};

const options = {
  //definitions to type cast
  typeHandlers: {
    Array:function(value,index,parent){
      return 'replaced-array';
    },
    Boolean:function(value,index,parent){
      return 'replaced-boolean';
    },
    Function:function(value,index,parent){
      return value();
    },
    Number:function(value,index,parent){
      return 'replaced-number';
    },
    String:function(value,index,parent){
      return 'replaced-string';
    },
    Buffer:function(value,index,parent){
      return value.toString();
    }
  }
};

jsonexport(contacts, options, function(err, csv) {
  if (err) return console.error(err);
  console.log(csv);
});

The output would be:

a,a2b
b,other field
x,replaced-number
z,bad ace

Date typeHandler?

var date = new Date();
jsonexport({
    a: date,
    b: true
}, {
    typeHandlers: {
        Object: (value, name) => {
            if (value instanceof Date) return date.toLocaleString();
            return value;
        }
    }
}, (err, csv) => {
    if (err) return console.error(err);
    console.log(csv);
});

When using typeHandlers, Do NOT do this

const options = {
  typeHandlers: {
    Object:function(value, index, parent){
      return 'EVERYTHING IS AN OBJECT';
    }
  }
};

It is NOT an error, however the recursive result becomes illegable functionality strings

Contributors

• Kauê Gimenes
• Pierre Guillaume
• Acker Apple
• Victor Hahn
• Jason Macgowan
• And many more...