More efficient way to async load javascript files - javascript

I am trying to load file files asynchronously with javascript, here is the code:
var jsFiles = [ 'js/enscroll.min.js',
'js/jp_custom.js',
'js/jquery.uploadifive.js',
'js/raphael-min.js',
'js/pgloader.js',
'js/jquery.custom.js' ];
for( var i=0, j=jsFiles.length; i < j; i++ ){
var file = jsFiles.shift();
asyncLoader(file, i);
}
function asyncLoader( filename, position, fileType ){
var type = typeof fileType == "undefined" ? "script" : fileType,
resource = document.createElement(type),
script = document.getElementsByTagName(type)[position+1];
resource.src = filename;
resource.type = "text/javascript";
script.parentNode.insertBefore(resource, script);
}
i am useing this code under the <head></head> tag means in the top of the file, and here is how do used the files related functionalities:
$(function(){
$(window).load(function(){
// Start to use the related files
});
})
at the bottom of the page so that after load the window my files working properly, i just want to know is this the best way to reduce the page load time(only javascript)? or what i have to with it to make it more efficient?

Related

How to add a file extension to file without any

so I've downloaded a few blank HTML files with no file extensions.
(I know these are HTML because if I manually add .HTML to the end and open the file, / the file contains html elements.... like etc.)
So they're located in my downloads folder. I'm simply trying to add a file extension to each of these files in the dir folder "download".
Here's my code:
var fs = require('fs');
var files = fs.readdirSync('C:/Users/Nikki/Downloads').forEach(file => {
console.log(file);
//There is a file named "desktop.ini", skip this file.
if (file === "desktop.ini") {
console.log("desktop file")
} else {
//not sure why it doesn't change the file extension. Maybe because there is none!?
var replaceExt = require('replace-ext');
var path = 'C:/Users/Nikki/Downloads/' + file;
var newPath = replaceExt(path, '.html');
console.log(newPath);
}
/*
fs.rename(file, file+'.html', () => {
console.log("\nFile Renamed!\n");
// doesnt work... either...
});
*/
});
How can I add the HTML file extension to each of these files?
If your file doesn't have a file extension, you can try the following code snippet :
var pos = file.lastIndexOf(".");
file = file.substr(0, pos < 0 ? file.length : pos) + ".html";

Using jQuery/javascript to dynamically add all images in a directory [duplicate]

I have a folder named "images" in the same directory as my .js file. I want to load all the images from "images" folder into my html page using Jquery/Javascript.
Since, names of images are not some successive integers, how am I supposed to load these images?
Works both localhost and on live server without issues, and allows you to extend the delimited list of allowed file-extensions:
var folder = "images/";
$.ajax({
url : folder,
success: function (data) {
$(data).find("a").attr("href", function (i, val) {
if( val.match(/\.(jpe?g|png|gif)$/) ) {
$("body").append( "<img src='"+ folder + val +"'>" );
}
});
}
});
NOTICE
Apache server has Option Indexes turned on by default - if you use another server like i.e. Express for Node you could use this NPM package for the above to work: https://github.com/expressjs/serve-index
If the files you want to get listed are in /images than inside your server.js you could add something like:
const express = require('express');
const app = express();
const path = require('path');
// Allow assets directory listings
const serveIndex = require('serve-index');
app.use('/images', serveIndex(path.join(__dirname, '/images')));
Use :
var dir = "Src/themes/base/images/";
var fileextension = ".png";
$.ajax({
//This will retrieve the contents of the folder if the folder is configured as 'browsable'
url: dir,
success: function (data) {
//List all .png file names in the page
$(data).find("a:contains(" + fileextension + ")").each(function () {
var filename = this.href.replace(window.location.host, "").replace("http://", "");
$("body").append("<img src='" + dir + filename + "'>");
});
}
});
If you have other extensions, you can make it an array and then go through that one by one using in_array().
P.s : The above source code is not tested.
This is the way to add more file extentions, in the example given by Roy M J in the top of this page.
var fileextension = [".png", ".jpg"];
$(data).find("a:contains(" + (fileextension[0]) + "), a:contains(" + (fileextension[1]) + ")").each(function () { // here comes the rest of the function made by Roy M J
In this example I have added more contains.
If interested in doing this without jQuery - here's a pure JS variant (from here) of the answer currently most upvoted:
var xhr = new XMLHttpRequest();
xhr.open("GET", "/img", true);
xhr.responseType = 'document';
xhr.onload = () => {
if (xhr.status === 200) {
var elements = xhr.response.getElementsByTagName("a");
for (x of elements) {
if ( x.href.match(/\.(jpe?g|png|gif)$/) ) {
let img = document.createElement("img");
img.src = x.href;
document.body.appendChild(img);
}
};
}
else {
alert('Request failed. Returned status of ' + xhr.status);
}
}
xhr.send()
Here is one way to do it. Involves doing a little PHP as well.
The PHP part:
$filenameArray = [];
$handle = opendir(dirname(realpath(__FILE__)).'/images/');
while($file = readdir($handle)){
if($file !== '.' && $file !== '..'){
array_push($filenameArray, "images/$file");
}
}
echo json_encode($filenameArray);
The jQuery part:
$.ajax({
url: "getImages.php",
dataType: "json",
success: function (data) {
$.each(data, function(i,filename) {
$('#imageDiv').prepend('<img src="'+ filename +'"><br>');
});
}
});
So basically you do a PHP file to return you the list of image filenames as JSON, grab that JSON using an ajax call, and prepend/append them to the html. You would probably want to filter the files u grab from the folder.
Had some help on the php part from 1
$(document).ready(function(){
var dir = "test/"; // folder location
var fileextension = ".jpg"; // image format
var i = "1";
$(function imageloop(){
$("<img />").attr('src', dir + i + fileextension ).appendTo(".testing");
if (i==13){
alert('loaded');
}
else{
i++;
imageloop();
};
});
});
For this script, I have named my image files in a folder as 1.jpg, 2.jpg, 3.jpg, ... to 13.jpg.
You can change directory and file names as you wish.
Based on the answer of Roko C. Buljan, I have created this method which gets images from a folder and its subfolders . This might need some error handling but works fine for a simple folder structure.
var findImages = function(){
var parentDir = "./Resource/materials/";
var fileCrowler = function(data){
var titlestr = $(data).filter('title').text();
// "Directory listing for /Resource/materials/xxx"
var thisDirectory = titlestr.slice(titlestr.indexOf('/'), titlestr.length)
//List all image file names in the page
$(data).find("a").attr("href", function (i, filename) {
if( filename.match(/\.(jpe?g|png|gif)$/) ) {
var fileNameWOExtension = filename.slice(0, filename.lastIndexOf('.'))
var img_html = "<img src='{0}' id='{1}' alt='{2}' width='75' height='75' hspace='2' vspace='2' onclick='onImageSelection(this);'>".format(thisDirectory + filename, fileNameWOExtension, fileNameWOExtension);
$("#image_pane").append(img_html);
}
else{
$.ajax({
url: thisDirectory + filename,
success: fileCrowler
});
}
});}
$.ajax({
url: parentDir,
success: fileCrowler
});
}
This is the code that works for me, what I want is to list the images directly on my page so that you just have to put the directory where you can find the images for example -> dir = "images /"
I do a substring var pathName = filename.substring (filename.lastIndexOf ('/') + 1);
with which I make sure to just bring the name of the files listed and at the end I link my URL to publish it in the body
$ ("body"). append ($ ("<img src =" + dir + pathName + "> </ img>"));
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title></title>
<script src="jquery-1.6.3.min.js"></script>
<script>
var dir = "imagenes/";
var fileextension = ".jpg";
$.ajax({
//This will retrieve the contents of the folder if the folder is configured as 'browsable'
url: dir,
success: function (data) {
//Lsit all png file names in the page
$(data).find("a:contains(" + fileextension + ")").each(function () {
var filename = this.href.replace(window.location.pathname, "").replace("http://", "");
var pathName = filename.substring(filename.lastIndexOf('/') + 1);
$("body").append($("<img src=" + dir + pathName + "></img>"));
console.log(dir+pathName);
});
}
});
</script>
</head>
<body>
<img src="1_1.jpg">
</body>
</html>
If, as in my case, you would like to load the images from a local folder on your own machine, then there is a simple way to do it with a very short Windows batch file. This uses the ability to send the output of any command to a file using > (to overwrite a file) and >> (to append to a file).
Potentially, you could output a list of filenames to a plain text file like this:
dir /B > filenames.txt
However, reading in a text file requires more faffing around, so I output a javascript file instead, which can then be loaded in your to create a global variable with all the filenames in it.
echo var g_FOLDER_CONTENTS = mlString(function() { /*! > folder_contents.js
dir /B images >> folder_contents.js
echo */}); >> folder_contents.js
The reason for the weird function with comment inside notation is to get around the limitation on multi-line strings in Javascript. The output of the dir command cannot be formatted to write a correct string, so I found a workaround here.
function mlString(f) {
return f.toString().
replace(/^[^\/]+\/\*!?/, '').
replace(/\*\/[^\/]+$/, '');
}
Add this in your main code before the generated javascript file is run, and then you will have a global variable called g_FOLDER_CONTENTS, which is a string containing the output from the dir command. This can then be tokenized and you'll have a list of filenames, with which you can do what you like.
var filenames = g_FOLDER_CONTENTS.match(/\S+/g);
Here's an example of it all put together: image_loader.zip
In the example, run.bat generates the Javascript file and opens index.html, so you needn't open index.html yourself.
NOTE: .bat is an executable type in Windows, so open them in a text editor before running if you are downloading from some random internet link like this one.
If you are running Linux or OSX, you can probably do something similar to the batch file and produce a correctly formatted javascript string without any of the mlString faff.
You can't do this automatically. Your JS can't see the files in the same directory as it.
Easiest is probably to give a list of those image names to your JavaScript.
Otherwise, you might be able to fetch a directory listing from the web server using JS and parse it to get the list of images.
In jQuery you can use Ajax to call a server-side script. The server-side script will find all the files in the folder and return them to your html file where you will need to process the returned information.
You can use the fs.readdir or fs.readdirSync methods to get the file names in the directory.
The difference between the two methods, is that the first one is asynchronous, so you have to provide a callback function that will be executed when the read process ends.
The second is synchronous, it will returns the file name array, but it will stop any further execution of your code until the read process ends.
After that you simply have to iterate through the names and using append function, add them to their appropriate locations. To check out how it works see HTML DOM and JS reference
Add the following script:
<script type="text/javascript">
function mlString(f) {
return f.toString().
replace(/^[^\/]+\/\*!?/, '');
replace(/\*\/[^\/]+$/, '');
}
function run_onload() {
console.log("Sample text for console");
var filenames = g_FOLDER_CONTENTS.match(/\S+/g);
var fragment = document.createDocumentFragment();
for (var i = 0; i < filenames.length; ++i) {
var extension = filenames[i].substring(filenames[i].length-3);
if (extension == "png" || extension == "jpg") {
var iDiv = document.createElement('div');
iDiv.id = 'images';
iDiv.className = 'item';
document.getElementById("image_div").appendChild(iDiv);
iDiv.appendChild(fragment);
var image = document.createElement("img");
image.className = "fancybox";
image.src = "images/" + filenames[i];
fragment.appendChild(image);
}
}
document.getElementById("images").appendChild(fragment);
}
</script>
then create a js file with the following:
var g_FOLDER_CONTENTS = mlString(function() { /*!
1.png
2.png
3.png
*/});
Using Chrome, searching for the images files in links (as proposed previously) didn't work as it is generating something like:
(...) i18nTemplate.process(document, loadTimeData);
</script>
<script>start("current directory...")</script>
<script>addRow("..","..",1,"170 B","10/2/15, 8:32:45 PM");</script>
<script>addRow("fotos-interessantes-11.jpg","fotos-interessantes-> 11.jpg",false,"","");</script>
Maybe the most reliable way is to do something like this:
var folder = "img/";
$.ajax({
url : folder,
success: function (data) {
var patt1 = /"([^"]*\.(jpe?g|png|gif))"/gi; // extract "*.jpeg" or "*.jpg" or "*.png" or "*.gif"
var result = data.match(patt1);
result = result.map(function(el) { return el.replace(/"/g, ""); }); // remove double quotes (") surrounding filename+extension // TODO: do this at regex!
var uniqueNames = []; // this array will help to remove duplicate images
$.each(result, function(i, el){
var el_url_encoded = encodeURIComponent(el); // avoid images with same name but converted to URL encoded
console.log("under analysis: " + el);
if($.inArray(el, uniqueNames) === -1 && $.inArray(el_url_encoded, uniqueNames) === -1){
console.log("adding " + el_url_encoded);
uniqueNames.push(el_url_encoded);
$("#slider").append( "<img src='" + el_url_encoded +"' alt=''>" ); // finaly add to HTML
} else{ console.log(el_url_encoded + " already in!"); }
});
},
error: function(xhr, textStatus, err) {
alert('Error: here we go...');
alert(textStatus);
alert(err);
alert("readyState: "+xhr.readyState+"\n xhrStatus: "+xhr.status);
alert("responseText: "+xhr.responseText);
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

How to connect html file with a js file from node_modules?

I'm trying to add \node_modules\sip.js\dist\sip.min.js , to my html file. I tried to import like import * as SIP from 'sip.js/dist/sip'; in my component.ts but this work only if I call some function from it. But I need my html file to read this sip.min.js.
Also I tried to download local this files and added in my html file
<script src="js/sip-0.5.0.js"></script>
<script src="js/ua.js"></script>
and added:
public loadScript() {
console.log("preparing to load...");
let node = document.createElement('script');
node.src = this.url;
node.type = "text/javascript";
node.async = true;
node.charset = "utf-8";
document.getElementsByTagName("head")[0].appendChild(node);
}
ngOnInit() {
this.loadAPI = new Promise(resolve => {
console.log("resolving promise...");
this.loadScript();
});
}
But this is not working
You could add them to body. Also your paths should be available from client side. But adding scripts in Init event is bad practice - it is added each time as component is created. I have added scripts in service - it executes once.
const files = ['js/sip-0.5.0.js','js/ua.js']
files.forEach((file) => {
const fileRef = document.createElement('script');
fileRef.setAttribute('type', 'text/javascript');
fileRef.setAttribute('src', file);
fileRef.onload = function () {
console.log('loaded' + file);
};
document.body.appendChild(fileRef);
});
But this approach is good only for dynamic adding scripts based on some condition. If your scripts are independent from other files you could just add it to bundle file without any manually struggling.

How to download multiple files with window.open()?

I am trying to download multiple files at once. At first I use window.location = url but now it doesn't seem to work.
I've changed it to window.open(url, "_blank") and it only downloads the first one:
window.open("/host/Controller/DownloadDasFiles?paramId=204");
window.open("/host/Controller/DownloadDasFiles?paramId=205");
window.open("/host/Controller/DownloadDasFiles?paramId=206");
public FileResult DownloadDasFiles(int paramId)
{
var dasControl = UnityConfig.container.Resolve<IDasControlService>();
var filename = dasControl.GetDasFileToDownload(paramId);
return File(filename, "application/octet-stream", Path.GetFileName(filename));
}
In my real case I do this after AJAX success in a javascript loop, but this code should work, shouldn't it?
This may help. It will open all 3 windows at same time.
let test = [204, 205, 206];
let downLoadFileBaseUrl = '/host/Controller/DownloadDasFiles?paramId='
test.forEach(element => {
let file = `${downLoadFileBaseUrl}+${element}`;
window.open(file, '_blank', 'File :' + element + ',scrollbars=1,menubar=0,resizable=1,width=850,height=500');
});

Load External Script and Style Files in a SPA

I have a type of SPA which consumes an API in order to fetch data. There are some instance of this SPA and all of them use common style and script files. So my problem is when I change a single line in those files, I will have to open each and every instances and update the files. It's really time consuming for me.
One of the approaches is to put those files in a folder in the server, then change the version based on the time, but I will lose browser cache if I use this solution:
<link href="myserver.co/static/main.css?ver=1892471298" rel="stylesheet" />
<script src="myserver.co/static/script.js?ver=1892471298"></script>
The ver value is produced based on time and I cannot use browser cache. I need a solution to update these files from the API, then all of the SPAs will be updated.
In your head tag, you can add the code below:
<script type="text/javascript">
var xmlhttp = new XMLHttpRequest();
var url = "http://localhost:4000/getLatestVersion"; //api path to get the latest version
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var tags = JSON.parse(xmlhttp.responseText);
for (var i = 0; i < tags.length; i++) {
var tag = document.createElement(tags[i].tag);
if (tags[i].tag === 'link') {
tag.rel = tags[i].rel;
tag.href = tags[i].url;
} else {
tag.src = tags[i].url;
}
document.head.appendChild(tag);
}
}
};
xmlhttp.open("POST", url, false);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send();
</script>
Your api path should allow "CORS" from your website that handles the code above.
And your api should return a json data like below:
var latestVersion = '1892471298'; //this can be stored in the database
var jsonData = [
{
tag: 'link',
rel: 'stylesheet',
url: 'http://myserver.co/static/main.css?ver=' + latestVersion
},
{
tag: 'script',
rel: '',
url: 'http://myserver.co/static/script.js?ver=' + latestVersion
}
];
//return jsonData to the client here
If you change anything in your JS or CSS then you have to update the browser cache, all you can do is to update that particular JS version not all of them, it should reflect in browser.
How about adding a method in your API returning the files' last modified time and then inserting the value into the "src"/"href" attribute after the "ver="

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