I am writing a program in Node.js using MongoDB and I want to update a database when certain files are modified. Inside the database I store the mtime of each database entry and I want to compare this to the mtime of the file to see if the database entry is out of date. Here is my code:

function updateArticles(articles) {

    const dir = articles;

    const files = fs.readdirSync(dir);



    files.forEach(

        (file) => {

            const fpath = path.join(dir, file);

            const fmtime = fs.statSync(fpath).mtimeMs;

            articles.updateOne(

                //refresh content and mtime if the text file has been modified

                {

                    _id: file,

                    mtime: {$lte: fmtime}

                },

                {

                    $set: {content: htmlifySync(fpath), mtime: Date.now(), title: titleSync(fpath)},

                    //btime is only set once

                    $setOnInsert: {btime: Date.now()}

                },

                {upsert: true}

            )

        });

}

When I set {upsert: true} I get a duplicate key error. When I set {upsert: false} new entries are not added. It works if I remove the second condition in my query but then it is running htmlifySync and titleSync for every entry which is expensive and unneccessary.

I think the issue is that mongoDB is trying to insert a new entry which meets both query conditions which means it tries to insert a new entry with the same id. I want mtime: {$lte: fmtime} to be a filter for the update but I don't want it to be made true by the update.

To clarify:

• If there is a DB entry for the file:
  
  
  
  
  • If the file has been modified since the last DB update I want to update it
  
  
  • If the file hasn't been modified since the last DB update I want to leave it unchanged
  
  


• If there isn't a DB entry for the file I want to create one