How to copy a file using Node.js

To copy a file in Nodejs:

1. Use the fs.copyFile() method from the native file system module.
2. Pass the source filename, the destination filename, an optional modifier for the copy operation, and a callback function as parameters.
3. The callback function gets called with an error object or null depending on the status of the copy operation.

Here is an example:

const fs = require('fs')

fs.copyFile('src.txt', 'dest.txt', err => {
  if (err) {
    console.error(err)
  }

  console.log(`src.txt was copied to dest.txt!`)
})

The fs.copyFile() method copies source file to destination file. By default, if the destination file already exists, it is overwritten.

However, you can pass an optional integer as a third parameter that specifies the behavior of the copy operation:

• fs.constants.COPYFILE_EXCL — The copy operation will fail if destination file already exists.
• fs.constants.COPYFILE_FICLONE — The copy operation will attempt to create a copy-on-write reflink. If the platform does not support copy-on-write, then a fallback copy mechanism is used.
• fs.constants.COPYFILE_FICLONE_FORCE — The copy operation will attempt to create a copy-on-write reflink. If the platform does not support copy-on-write, then the operation will fail.

// Fail if dest.txt already exists
fs.copyFile('src.txt', 'dest.txt', fs.constants.COPYFILE_EXCL, err => {
  if (err) {
    console.error(err)
  }

  console.log(`src.txt was copied to dest.txt!`)
})

To synchronously copy the source file to the destination file, use the fs.copyFileSync() method instead:

const fs = require('fs')

fs.copyFile('src.txt', 'dest.txt')
console.log(`src.txt was copied to dest.txt!`)

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