how to use the ftruncate function from fs-extra in javascript

To use ftruncate function from fs-extra in JavaScript, you'll first need to install the fs-extra package by running the following command in your terminal or command prompt:

index.tsx
npm install fs-extra
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After that, you can use ftruncate function by importing it from fs-extra and passing in the file descriptor and the desired length as parameters. Here's an example:

index.tsx
const fs = require('fs-extra');

const file = 'example.txt';
const length = 100; // new length of the file in bytes

// open file and get its descriptor
const fd = fs.openSync(file, 'r+');

// truncate the file to the desired length
fs.ftruncate(fd, length, (err) => {
  if (err) {
    console.error(err);
  } else {
    console.log(`File ${file} truncated to ${length} bytes`);
  }
});

// close the file descriptor
fs.closeSync(fd);
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In this example, we first define the path to the file and the desired length that we want to truncate it to. Then, we use fs.openSync method to get the file descriptor, and pass it along with the desired length to fs.ftruncate function. The err parameter in the callback function is used to handle any errors that may occur during the truncation process.

After that, we log a message to the console if the file was successfully truncated, and close the file descriptor by using the fs.closeSync method.