Node.js - jsonfile
================
Easily read/write JSON files in Node.js. _Note: this module cannot be used in the browser._
[](https://www.npmjs.org/package/jsonfile)
[](http://travis-ci.org/jprichardson/node-jsonfile)
[](https://ci.appveyor.com/project/jprichardson/node-jsonfile/branch/master)
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)`](#readfilefilename-options-callback)
* [`readFileSync(filename, [options])`](#readfilesyncfilename-options)
* [`writeFile(filename, obj, [options], callback)`](#writefilefilename-obj-options-callback)
* [`writeFileSync(filename, obj, [options])`](#writefilesyncfilename-obj-options)
----
### readFile(filename, [options], callback)
`options` (`object`, default `undefined`): Pass in any [`fs.readFile`](https://nodejs.org/api/fs.html#fs_fs_readfile_path_options_callback) options or set `reviver` for a [JSON reviver](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse).
- `throws` (`boolean`, default: `true`). If `JSON.parse` throws an error, pass this error to the callback.
If `false`, returns `null` for the object.
```js
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.
```js
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`](https://nodejs.org/api/fs.html#fs_fs_readfilesync_path_options) options or set `reviver` for a [JSON reviver](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse).
- `throws` (`boolean`, default: `true`). If an error is encountered reading or parsing the file, throw the error. If `false`, returns `null` for the object.
```js
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`](https://nodejs.org/api/fs.html#fs_fs_writefile_file_data_options_callback) options or set `replacer` for a [JSON replacer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify). 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.
```js
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:
```js
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:**
```js
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:**
```js
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:**
```js
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.
```js
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`](https://nodejs.org/api/fs.html#fs_fs_writefilesync_file_data_options) options or set `replacer` for a [JSON replacer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify). 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.
```js
const jsonfile = require('jsonfile')
const file = '/tmp/data.json'
const obj = { name: 'JP' }
jsonfile.writeFileSync(file, obj)
```
**formatting with spaces:**
```js
const jsonfile = require('jsonfile')
const file = '/tmp/data.json'
const obj = { name: 'JP' }
jsonfile.writeFileSync(file, obj, { spaces: 2 })
```
**overriding EOL:**
```js
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:**
```js
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.
```js
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