Checking if writeFileSync successfully wrote the file

I have a simple route defined with express.js:

exports.save = function (request, response)
{
    var file = request.body.file;
    var content = request.body.content;

    var saved = false;

    if (fs.existsSync( file ))
    {
        saved = fs.writeFileSync(file, content, 'utf8');
    }

    console.log( saved ); // undefined or false, never true

    response.send(saved ? 200 : 500, saved ? 'saved' : 'error'); // 500, error
};

Is if (typeof saved === 'undefined') saved = true; the only option? Feels hacky.

According to node.js source-code fs.writeFileSync doesn't return anything.

It throws an Error object if something goes wrong. So you should write fs.writeFileSync(file, content, 'utf8'); within a try-catch block.

fs.writeFileSync does not return any value, if there is no exception happens that means the save succeeded; otherwise failed.

you may want to try the async version of file read

fs.exists(file, function (exists) {
  if (exists) {
    fs.writeFiles(file, content, 'utf-8', function (err) {
      if (err) {
        response.send("failed to save");
      } else {
        response.send("succeeded in saving");
      }
  } else {
    console.log('file does not exists');
  }
}

 fs.exists(file, function (exists) {
  if (exists) {
    fs.writeFiles(file, content,  err=> {
      if (err)   res.status(500).send({error: "failed to save"});
       else    res.status(200).send({message : "succeeded in saving"});
  } else {
    res.status(404).send({error: "file not exists"})
  }
}

Use async instead of sync. This will work.