"'cb' argument must be of type function" error, invoking fs.writeFile()

I wrote this code:

var fs = require('fs');

var data = {
    name:'Bob'
}

and I get this error:

fs.writeFile('data.json',data) "the 'cb' argument must be of type function. Received undefined"

How do I fix it?

You're using the asynchronous callback-style fs.writeFile API without a callback (cb for short).

In addition, you're not encoding your data to JSON before attempting to write it, so that too would fail.

Either:

• use fs.writeFileSync() for synchronous file writing:

  fs.writeFileSync("data.json", JSON.stringify(data));
  

• pass in a callback (that can be anything, but it needs to be there):

  fs.writeFile("data.json", JSON.stringify(data), (err) => err && console.error(err));
  

• use fs/promises's promise-based asynchronous API:

  var fsp = require('fs/promises');
  await fsp.writeFile("data.json", JSON.stringify(data));