fs.stat failing to identify existing files - node.js

Question

I am using async.each to check through an array of 180 filenames, using fs.stat to check that the physical file exists. At present, all the files do exist, and yet every time I call this code, 3 of the 180 images are found by fs.stat to be non-existent. The images which it fails to find vary slightly on each call.
The first image which fails to be found is always around the 70th filename in the array. If I reduce the size of the array to a list of (for example) 50 names, then all the images are found.
// ImagesToCheck is an array of 180 filepaths, all of which exist on the server
var index = 0
async.each(ImagesToCheck,
function(item, cb) {
fs.stat(item, function(error, value) {
if (error) {
// Logs "ENOENT: no such file or directory"
console.log("error is "+error)
// this is logging the correct filename, which DOES exist
console.log("filename is "+ImagesToCheck[index])
Speakers[index].speaker_image_url = null
index++
cb()
}
else {
// Image exists
// console.log("image exists " + index)
Speakers[index].speaker_image_url = "http://www.apiurl.co.uk/images/seminar_image-" + rows[index].seminar_id + ".jpg"
index++
cb()
}
}) // close fs.stat
},
function(err) {
// sends the array of URLs
callBack(Speakers)
})
// Now using fs.open instead of fs.stat, with async.forEachOf, and getting basically the same result:
var index = 0
async.forEachOf(ImagesToCheck,
function(item, key, cb) {
fs.open(item, 'r', function(error, value) {
if (error) {
// Logs "ENOENT: no such file or directory"
console.log("error is " + error)
// this is logging the correct filename, which DOES exist
console.log("index is " + index + ", filename is " + ImagesToCheck[index])
Speakers[index].speaker_image_url = null
index++
return cb()
}
// if no error
Speakers[index].speaker_image_url = "http://www.apiurl.co.uk/images/seminar_image-" + rows[index].seminar_id + ".jpg"
index++
cb()
})
},
function(err) {
// send the array of urls
callBack(Speakers)
}
)

Answer 1

Note: This is just to show a test implementation. This is not intended as a answer
Just tried to generate 200 files (0.txt, 1.txt... 200.txt) in a folder named files, and tried this code:
'use strict';
const fs = require('fs'),
async = require('async');
let files = [],
results = [],
i = 0;
while(i < 200) {
files.push('./files/' + i + '.txt');
i = i + 1;
}
async.eachOf(files, (file, i, callback) => {
fs.stat(file, (err, stats) => {
files[i] = !err;
callback();
});
}, () => {
let notFound = files.filter((f) => {
return !f;
});
console.log('fs.stat didn\'t found ' + notFound.length + '/200 files');
files.map((f, i) => {
if(!f) {
console.log('File ' + i + ' wasn\'t found');
}
})
});
No error found, it seems the problem is not fs.stat