How to read list of files from directory, sorted on date modified, in Node JS

Question

Need to read list of files from particular directory with Date modified by descending or ascending in Node js.

I have tried below code but could not get the solution.

fs.readdir(path, function (err, files) {
                    if (err) throw err;
                    else {
                        var res = [];
                        files.forEach(function (file) {
                            if (file.split('.')[1] == "json") {
                                fs.stat(path, function (err, stats) {                                                                  

                                });
                                res.push(file.substring(0, file.length - 5));
                            }
                        });
                    }  

stats parameter give mtime as modified time?

Is there any way to get files with modified date.

Answer 1

mtime gives Unix timestamp. You can easily convert to Date as,
const date = new Date(mtime);

And for your sorting question, you can do as following

var dir = 'mydir/';

fs.readdir(dir, function(err, files){
  files = files.map(function (fileName) {
    return {
      name: fileName,
      time: fs.statSync(dir + '/' + fileName).mtime.getTime()
    };
  })
  .sort(function (a, b) {
    return a.time - b.time; })
  .map(function (v) {
    return v.name; });
});  

files will be an array of files in ascending order.
For descending, just replace a.time with b.time, like b.time - a.time

UPDATE: ES6+ version

const myDir = 'mydir';

const getSortedFiles = async (dir) => {
  const files = await fs.promises.readdir(dir);

  return files
    .map(fileName => ({
      name: fileName,
      time: fs.statSync(`${dir}/${fileName}`).mtime.getTime(),
    }))
    .sort((a, b) => a.time - b.time)
    .map(file => file.name);
};

getSortedFiles(myDir)
  .then(console.log)
  .catch(console.error);

Answer 2

The solution with the streams works well. But incase you do not want to use streams, you may use statsSync as follows:

 //import the fs
const fs = require("fs");

//list with statSync
//I added letters at the start of the files names so that the alphabetical order becomes different from the chronollogical
fs.readdir("./anville95/", (error, files) => {
    if(error) {
        console.log("Sorry lad, I was unable to read the files!");
        return;
    }
    console.log("Before sorting with the last modification time...");
    console.log(files);
    //compare each file with each and every file using their milliseconds modification time and swap if necessary
    for(var i = 0; i < files.length; i++) {
        for(var j = 0; j < files.length; j++) {
            //create the stats files
            var firstFileStats = fs.statSync("./anville95/" + files[i]);
            var secondFileStats = fs.statSync("./anville95/" + files[j]);
            //if files[i] comes before files[j] and files[i] modification time is older than files[j] modification time, swap them
            if(i < j && firstFileStats.mtimeMs > secondFileStats.mtimeMs) {
                var swap = files[i];
                files[i] = files[j];
                files[j] = swap;
            }
        }
    }
    //At this point, the swapping is done thus I print out the results
    console.log("After sorting chronollogically with statSync().mtimeMs...");
    console.log(files);
});

Here are the screenshots I took of my results during its execution. Thank you for reading, happy coding.

Answer 3

I have got the answer using sorting operation.

fs.stat(path, function (err, stats) {
                        res.push(file.substring(0, file.length - 5) + '&' + stats.mtime);
                    });

stored mtime to an array and sort that array using sorting technique in below url.

Simple bubble sort c#