Node.js fs.filehandle.sync() Method
The fs.filehandle.sync() method is an inbuilt application programming interface of class fs.filehandle within File System module which is used to synchronize this file’s in-core state with the storage device.
Syntax:
const filehandle.sync()
Parameter: This method does not accept any argument as parameter.
Return Value: This method returns a pending promise which contains no value in it.
Below programs illustrates the use of fs.filehandle.sync() method.
Example 1: Filename: index.js
- javascript
javascript
// Node.js program to demonstrate the // filehandle.sync() methodconst fs = require('fs');const fsPromises = fs.promises;console.log("content of file before operation :- " + (fs.readFileSync('example.txt')));// Initiating asynchronise functionasync function funct() { // Initializing following variables let filehandle = null; let prom = null; try { // Creating and initiating filehandle filehandle = await fsPromises.open('example.txt', 'r+'); // Synchronizing the file's in-core state // by using sync() method prom = filehandle.sync(); } finally { if (filehandle) { // Display the result console.log("data is synchronized successfully"); console.log("content of file after operation :- " + (fs.readFileSync('example.txt'))); // Close the file if it is opened. await filehandle.close(); } }}funct().catch(console.error); |
Directory structure before running the program:
Directory structure after running the program:
Run index.js file using the following command:
node index.js
Output:
content of file before operation :- Content of file: example.txt data is synchronized successfully content of file after operation :- Content of file: example.txt
Example 2: Filename: index.js
- javascript
javascript
// Node.js program to demonstrate the // filehandle.sync() methodconst fs = require('fs');const fsPromises = fs.promises;// Data for the new filelet data = "This is a file containing" + " a collection of books.";// Name of the file to be createdlet file = "books.txt";// Creating the new file 'books.txt'fs.writeFile(file, data, (err) => { // Catching error if (err) { console.log(err); }});// Using fs.exists() method fs.exists(file, (exists) => { if (exists) { console.log("content of file before" + " operation :- " + (fs.readFileSync(file))); }});// Initiating asynchronise functionasync function funct() { // Initializing filehandle let filehandle = null; try { // Creating and initiating filehandle filehandle = await fsPromises.open(file, 'r+'); // Synchronizing the file's in-core // state by using sync() method prom = filehandle.sync(); } finally { if (filehandle) { // Close the file if it is opened. console.log("data is synchronized" + " successfully"); console.log("content of file after" + " operation :- " + (fs.readFileSync(file))); await filehandle.close(); } }}funct().catch(console.error); |
Directory structure before running the program:
Directory structure after running the program:
Run index.js file using the following command:
node index.js
Output:
content of file before operation :- This is a file containing a collection of books.
data is synchronized successfully
content of file after operation :- This is a file containing a collection of books.
