187 lines
4.6 KiB
Markdown
187 lines
4.6 KiB
Markdown
Node.js - jsonfile
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================
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Easily read/write JSON files.
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[](https://www.npmjs.org/package/jsonfile)
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[](http://travis-ci.org/jprichardson/node-jsonfile)
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[](https://ci.appveyor.com/project/jprichardson/node-jsonfile/branch/master)
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<a href="https://github.com/feross/standard"><img src="https://cdn.rawgit.com/feross/standard/master/sticker.svg" alt="Standard JavaScript" width="100"></a>
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Why?
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----
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Writing `JSON.stringify()` and then `fs.writeFile()` and `JSON.parse()` with `fs.readFile()` enclosed in `try/catch` blocks became annoying.
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Installation
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------------
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npm install --save jsonfile
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API
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---
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### readFile(filename, [options], callback)
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`options` (`object`, default `undefined`): Pass in any `fs.readFile` options or set `reviver` for a [JSON reviver](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse).
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- `throws` (`boolean`, default: `true`). If `JSON.parse` throws an error, pass this error to the callback.
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If `false`, returns `null` for the object.
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/data.json'
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jsonfile.readFile(file, function(err, obj) {
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console.dir(obj)
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})
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```
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### readFileSync(filename, [options])
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`options` (`object`, default `undefined`): Pass in any `fs.readFileSync` options or set `reviver` for a [JSON reviver](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse).
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- `throws` (`boolean`, default: `true`). If an error is encountered reading or parsing the file, throw the error. If `false`, returns `null` for the object.
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/data.json'
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console.dir(jsonfile.readFileSync(file))
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```
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### writeFile(filename, obj, [options], callback)
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`options`: Pass in any `fs.writeFile` 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`.
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/data.json'
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var obj = {name: 'JP'}
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jsonfile.writeFile(file, obj, function (err) {
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console.error(err)
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})
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```
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**formatting with spaces:**
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/data.json'
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var obj = {name: 'JP'}
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jsonfile.writeFile(file, obj, {spaces: 2}, function(err) {
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console.error(err)
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})
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```
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**appending to an existing JSON file:**
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You can use `fs.writeFile` option `{flag: 'a'}` to achieve this.
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/mayAlreadyExistedData.json'
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var obj = {name: 'JP'}
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jsonfile.writeFile(file, obj, {flag: 'a'}, function (err) {
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console.error(err)
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})
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```
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### writeFileSync(filename, obj, [options])
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`options`: Pass in any `fs.writeFileSync` 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`.
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/data.json'
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var obj = {name: 'JP'}
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jsonfile.writeFileSync(file, obj)
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```
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**formatting with spaces:**
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/data.json'
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var obj = {name: 'JP'}
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jsonfile.writeFileSync(file, obj, {spaces: 2})
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```
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**appending to an existing JSON file:**
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You can use `fs.writeFileSync` option `{flag: 'a'}` to achieve this.
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```js
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var jsonfile = require('jsonfile')
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var file = '/tmp/mayAlreadyExistedData.json'
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var obj = {name: 'JP'}
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jsonfile.writeFileSync(file, obj, {flag: 'a'})
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```
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### spaces
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Global configuration to set spaces to indent JSON files.
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**default:** `null`
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```js
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var jsonfile = require('jsonfile')
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jsonfile.spaces = 4
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var file = '/tmp/data.json'
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var obj = {name: 'JP'}
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// json file has four space indenting now
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jsonfile.writeFile(file, obj, function (err) {
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console.error(err)
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})
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```
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Note, it's bound to `this.spaces`. So, if you do this:
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```js
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var myObj = {}
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myObj.writeJsonSync = jsonfile.writeFileSync
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// => this.spaces = null
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```
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Could do the following:
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```js
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var jsonfile = require('jsonfile')
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jsonfile.spaces = 4
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jsonfile.writeFileSync(file, obj) // will have 4 spaces indentation
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var myCrazyObj = {spaces: 32}
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myCrazyObj.writeJsonSync = jsonfile.writeFileSync
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myCrazyObj.writeJsonSync(file, obj) // will have 32 space indentation
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myCrazyObj.writeJsonSync(file, obj, {spaces: 2}) // will have only 2
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```
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License
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-------
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(MIT License)
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Copyright 2012-2016, JP Richardson <jprichardson@gmail.com>
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