Node.js fs.filehandle.sync() Method
Last Updated :
28 Dec, 2022
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
const fs = require( 'fs' );
const fsPromises = fs.promises;
console.log( "content of file before operation :- "
+ (fs.readFileSync( 'example.txt' )));
async function funct() {
let filehandle = null ;
let prom = null ;
try {
filehandle = await
fsPromises.open( 'example.txt' , 'r+' );
prom = filehandle.sync();
} finally {
if (filehandle) {
console.log( "data is synchronized successfully" );
console.log( "content of file after operation :- "
+ (fs.readFileSync('example.txt')));
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
const fs = require( 'fs' );
const fsPromises = fs.promises;
let data = "This is a file containing"
+ " a collection of books." ;
let file = "books.txt" ;
fs.writeFile(file, data, (err) => {
if (err) {
console.log(err);
}
});
fs.exists(file, (exists) => {
if (exists) {
console.log( "content of file before"
+ " operation :- " +
(fs.readFileSync(file)));
}
});
async function funct() {
let filehandle = null ;
try {
filehandle = await
fsPromises.open(file, 'r+' );
prom = filehandle.sync();
} finally {
if (filehandle) {
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.
Reference: https://nodejs.org/dist/latest-v12.x/docs/api/fs.html#fs_filehandle_sync
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