jsonfile

Node.js - jsonfile

Easily read/write JSON files in Node.js. Note: this module cannot be used in the browser.

Why?

Writing JSON.stringify() and then fs.writeFile() and JSON.parse() with fs.readFile() enclosed in try/catch blocks became annoying.

Installation

npm install --save jsonfile

API

• readFile(filename, [options], callback)
• readFileSync(filename, [options])
• writeFile(filename, obj, [options], callback)
• writeFileSync(filename, obj, [options])

readFile(filename, [options], callback)

options (object, default undefined): Pass in any fs.readFile options or set reviver for a JSON reviver.

• throws (boolean, default: true). If JSON.parse throws an error, pass this error to the callback. If false, returns null for the object.

const jsonfile = require('jsonfile')
const file = '/tmp/data.json'
jsonfile.readFile(file, function (err, obj) {
  if (err) console.error(err)
  console.dir(obj)
})

You can also use this method with promises. The readFile method will return a promise if you do not pass a callback function.

const jsonfile = require('jsonfile')
const file = '/tmp/data.json'
jsonfile.readFile(file)
  .then(obj => console.dir(obj))
  .catch(error => console.error(error))

readFileSync(filename, [options])

options (object, default undefined): Pass in any fs.readFileSync options or set reviver for a JSON reviver.

• throws (boolean, default: true). If an error is encountered reading or parsing the file, throw the error. If false, returns null for the object.

const jsonfile = require('jsonfile')
const file = '/tmp/data.json'

console.dir(jsonfile.readFileSync(file))

writeFile(filename, obj, [options], callback)

options: Pass in any fs.writeFile options or set replacer for a JSON replacer. Can also pass in spaces, or override EOL string or set finalEOL flag as false to not save the file with EOL at the end.

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFile(file, obj, function (err) {
  if (err) console.error(err)
})

Or use with promises as follows:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFile(file, obj)
  .then(res => {
    console.log('Write complete')
  })
  .catch(error => console.error(error))

formatting with spaces:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFile(file, obj, { spaces: 2 }, function (err) {
  if (err) console.error(err)
})

overriding EOL:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFile(file, obj, { spaces: 2, EOL: '\r\n' }, function (err) {
  if (err) console.error(err)
})

disabling the EOL at the end of file:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFile(file, obj, { spaces: 2, finalEOL: false }, function (err) {
  if (err) console.log(err)
})

appending to an existing JSON file:

You can use fs.writeFile option { flag: 'a' } to achieve this.

const jsonfile = require('jsonfile')

const file = '/tmp/mayAlreadyExistedData.json'
const obj = { name: 'JP' }

jsonfile.writeFile(file, obj, { flag: 'a' }, function (err) {
  if (err) console.error(err)
})

writeFileSync(filename, obj, [options])

options: Pass in any fs.writeFileSync options or set replacer for a JSON replacer. Can also pass in spaces, or override EOL string or set finalEOL flag as false to not save the file with EOL at the end.

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFileSync(file, obj)

formatting with spaces:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFileSync(file, obj, { spaces: 2 })

overriding EOL:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFileSync(file, obj, { spaces: 2, EOL: '\r\n' })

disabling the EOL at the end of file:

const jsonfile = require('jsonfile')

const file = '/tmp/data.json'
const obj = { name: 'JP' }

jsonfile.writeFileSync(file, obj, { spaces: 2, finalEOL: false })

appending to an existing JSON file:

You can use fs.writeFileSync option { flag: 'a' } to achieve this.

const jsonfile = require('jsonfile')

const file = '/tmp/mayAlreadyExistedData.json'
const obj = { name: 'JP' }

jsonfile.writeFileSync(file, obj, { flag: 'a' })

License

(MIT License)

Copyright 2012-2016, JP Richardson [e-mail]

Similar packages

Other packages similar to jsonfile

fs-extra

fs-extra is a package that builds on the native fs module, providing additional methods and functionality. It includes methods for JSON file handling similar to jsonfile, such as readJson, writeJson, readJsonSync, and writeJsonSync. fs-extra offers a broader set of file system operations, making it a more comprehensive choice for general file system tasks.

fs-jetpack

fs-jetpack is another file system library that offers a fluent API for file operations. It includes read and write functionalities for JSON files with methods like readAsync, writeAsync, read, and write. fs-jetpack provides a different API design and additional file manipulation methods, which might be preferred by some developers for its convenience and chaining capabilities.