how to check if file exists in javascript code example

Example 1: node check if file exists

const fs = require('fs');

let file = '../path/to/chad_warden.mpeg';

// async
const fileExists = (file) => {
    return new Promise((resolve) => {
        fs.access(file, fs.constants.F_OK, (err) => {
            err ? resolve(false) : resolve(true)
        });
    })
}

// sync
const fileExistsSync = (file) => {
    try {
        fs.accessSync(file, fs.constants.R_OK | fs.constants.W_OK);
        return true;
      } catch (err) {
        return false;
      }
}

Example 2: javascript check if file exists on server

function doesFileExist(urlToFile) {
    var xhr = new XMLHttpRequest();
    xhr.open('HEAD', urlToFile, false);
    xhr.send();
     
    if (xhr.status == "404") {
        return false;
    } else {
        return true;
    }
}

Example 3: javascript file exists check

// checking existence of file synchronously
function doesFileExist(urlToFile) {
    var xhr = new XMLHttpRequest();
    xhr.open('HEAD', urlToFile, false);
    xhr.send();
     
    return xhr.status !== 404;
}

Example 4: check if file exists javascript

function executeIfFileExist(src, callback) {
    var xhr = new XMLHttpRequest()
    xhr.onreadystatechange = function() {
        if (this.readyState === this.DONE) {
            callback()
        }
    }
    xhr.open('HEAD', src)
}