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)
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 jprichardson@gmail.com
