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readJson() function in fs-extra - NodeJS
readJson() method reads a JSON object and then parses it into an object.
Syntax
readJson(file [, options] [, callback])
Parameters
file – String parameter which will contain name and location of the file holding the JSON.
options – The 'outputFile' function supports the following options −
encoding – Default 'null'.
flag – Default 'r'. The flag 'r' opens a file for reading and an exception will occur if file does not exist.
signal – allows aborting an ongoing output file function
callback – This function will give a callback if any error occurs.
Example 1
Check that fs-extra is installed before proceeding; if not, install fs-exra.
You can use the following command to check whether fs-extra is installed or not.
npm ls fs-extra
Create an asyncReadJsonExample.js and copy-paste the following code snippet into that file.
Now, run the following command to run the following code snippet.
node asyncReadJsonExample.js
Code Snippet −
const fs = require('fs-extra')
// Reading JSON with a callback:
fs.readJson('./package.json', (err, packageObj) => {
if (err) console.error(err)
console.log(packageObj.version) // => 1.0.0
})
// Reading JSON Promises:
fs.readJson('./package.json')
.then(packageObj => {
console.log(packageObj.version) // => 1.0.0
})
.catch(err => {
console.error(err)
})
// Reading JSON withasync/await:
async function asyncReadJsonExample () {
try {
const packageObj = await fs.readJson('./package.json')
console.log(packageObj.version) // => 1.0.0
} catch (err) {
console.error(err)
}
}
asyncReadJsonExample()Output
C:\Users\tutorialsPoint\> node asyncReadJsonExample.js 1.0.0 1.0.0 1.0.0
Introduction to readJsonSync()
This method reads JSON and parses it into an object.
Syntax
readJsonSync(file, [, options])
Parameters
file – This is a string paramter which will hold the location of the file.
options – The 'outputFile' function supports the following options −
encoding – Default 'null'.
flag – Default 'r'. The flag 'r' opens a file for reading and an exception will occur if file does not exist.
Example
Check that fs-extra is installed before proceeding; if not, install fs-exra.
You can use the following command to check whether fs-extra is installed or not.
npm ls fs-extra
Create a readJsonSyncExample.js and copy-paste the following code snippet into that file.
Now, run the following command to run the following code snippet.
node readJsonSyncExample.js
Code Snippet −
const fs = require('fs-extra')
const packageObj = fs.readJsonSync('./package.json')
console.log(packageObj.version) // => 1.0.0Output
C:\Users\tutorialsPoint\> node readJsonSyncExample.js 1.0.0
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