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NodeJs temporary file creation, serve and deletion using tmp or something else

I am trying to make a compiler in which users make code at abc.com/newProject and their output is in an iframe, that iframe need to be served files that are made at the abc.com/newProject. So I will be doing a POST of JSON obj at abc.com/compile-project that will create files and those will be used by the iframe, after being used those should get deleted. Files are basically JS files that iframe will fetch using script in header.
So a pseudo-code will look something like this:-
app.post('/compile-project', function(req, res){
//Directory created using node tmp
//files created in the directory
//These files are accessible using <script src="/js/file1.js"></script>
//when the current connection requests the files they get deleted
});
Any help will be appreciated thanks.....

I am trying to make a compiler [...] Any help will be appreciated thanks.....
I would strongly discourage you from doing that if you don't know what you're doing (and considering the fact that you're asking how to save a file then apparently you don't).
The requirements that you described are extremely simple but you need to have much deeper understanding of everything that's going on to avoid serious security problems that you will encounter with no doubt along the way.
What you describes can be done without even using a file system, since all your files are served only once so it doesn't make much sense to store them in actual files. But even if you insist on the file system then all you need is to use fs.mkdtemp to create a temporary directory, use something like the uuid module for unique IDs to use in the filenames, then use fs.writeFile to write a file. This is all you need for the file upload endpoint. Now in the download endpoint all you need is to use fs.readFile to read the file and fs.unlink to remove it. That's it.
Now, it will surely get you into trouble of failures on browser reloads, back button not working, and finally security issues of people being able to serve any random code from your servers leading to vulnerabilities too numerous to even list here.
Take a look at the source code of repl.it and JS Bin on GitHub:
https://github.com/replit/repl.it
https://github.com/jsbin/jsbin
to appreciate the scope of the project that you are willing to undertake.

Uncaught SyntaxError: Unexpected token < on each js file that invoked in the index html

I am using mean stack to build a website, when testing, chrome returns the error like:
Uncaught SyntaxError: Unexpected token < angular.js:1.
I don't know what's wrong and what should i do.
Here is the directory of my app:
E-study
-client
-app
-components
-all the libraries are here.
-index.html
-controllers.js
-node_modules
-server
-config
-server.js
And I run the server in E-study like :node server/config/server.js
The scripts in the index.html is<script src="client/components/angular/angular.js"></script>
Just don't know why all the js files are changed to index.html when open in the browser.

open up those library files and see if there are some extra symbol < probably you will find it in the beginning.. if still not able to fix... simply download the fresh library (if those are libraries) from the internet and try again.
make sure that you don't put <script> </script> tags in the included .js files. that is an incorrect syntax for script files.
also make sure you are providing the correct path??? providing incorrect path can return a builtin customized error page. which is html. may be that is the source of error because returned page is HTML which is most likely going to start with a < symbol. and offcourse not a js file.
to ensure that the incorrect path is the issue just copy the path you included in the code and and paste into your favorite browsers url bar and hit enter. if you are not getting the script in plain text.. then it means you are not providing the correct path.
and if it is return a customized error page like .. 404 not found then probably it is returning the html and this is where the error is coming from.

In external js files, which you refer in some other files, don't use <script>..</script> tag.

For express server try to set the static path to entire project folder.It worked for me
app.use(express.static(__dirname ));

Could be a ReCaptcha bot checker type thing intercepting requests for JS files and serving up an HTML page instead, which is invalid HTML so it throws the < is invalid message error.
I know siteground specifically has issues with this intercepting CDN routed traffic.
Check with the host to remove this issue, in this case it's their anti-bot security setup. This has remedied these issues with Siteground for me.

External javascript in html is sent incorrectly to the server

I'm running a Node.js server along with an Angular frontend. One of the Angular dependencies I'm using requires me to import a javascript file into my html page, by the name of swing.js. However, when I try to do this, it sends the required file as an http request to the server, resulting in requests that look like the following:
http://localhost:3000/home/me/app/node_modules/angular-swing/dist/swing.js
Obviously, this comes up as a 404. As an alternative, I've tried changing
<script src="/home/me/app/node_modules/angular-swing/dist/swing.js"></script>
into
<script src="swing.js"></script>
and then on the server-side, doing:
app.get('swing.js', function(req, res){
res.sendFile('home/me/app/node_modules/angular-swing/dist/swing.js');
});
This works a little more, but then the file doesn't run properly, as I'm assuming it's no longer in the npm environment it needs to be in. I've tried multiple iterations of changing
<script src="/home/me/app/node_modules/angular-swing/dist/swing.js"></script>
into something that uses periods (.) to represent more relative paths, but that doesn't appear to work either. Overall, I'm very stuck, and would appreciate any insight. If it's of any use, I'm also using:
app.use(express.static(__dirname+'/public'));

Making my comments into an answer...
node.js does not serve any files by default so any script files that you need sent from your server to the client upon request need an explicit route to handle them or they need some generic route that knows how to handle all the requested script files.
swing.js in the client is not part of any "NPM environment". It's running the browser at that point, not in any NPM enviornment. It's possible that swing.js itself needs some other scripts or resources that also need routes and that's why it doesn't work after you make an explicit route for it. You can probably examine the specific errors in the console to give you a clue why it isn't working.
You may also want to read this: How to include scripts located inside the node_modules folder?

cannot find js file

I have stucture code like this:
I try to load javascript into php file like this:
But i have an error like this:
This is my html :
And this is another javascript:
And i try to copy paste the link, and i got an error 404 not found. How can i fix it? Thanks.

Permissions
When the host is correct, and the file is in the right place, and you have no other networking problems, you may sometimes still get a 404 because of bad file permissions. If a server does not have permission to access a file, it may send out a 404 error in response. The reason why some "Not Authorized" error is not given instead, is that this would reveal more information about the files than you, the owner of the server, may intend. The way to respond to requests for privileged files without revealing whether or not they exist is to give a 404.
On Windows, you can view and change the permissions from the File Explorer by right-clicking on the file or folder, then going to Properties -> Security -> Edit. For more information, see the notes on permissions on Microsoft's site.
File Types
Besides permissions, a server must also be configured to serve the type of file you are accessing. If files with different extensions are served, but .js files are not, check the configuration of your server to make sure that .js files aren't blacklisted (or not whitelisted, as the case may be).
Directory Location
You should also verify that the files are actually stored in the top-most directory of the web server if that's how you are accessing them. If they aren't, you may need to prefix the path with the path from the webserver root to your application directory. E.g., instead of fusioncharts/..., you may need /path/to/fusioncharts/... or ../../path/to/fusioncharts.
Other Considerations
In your particular case, you should also verify that the files inside the fusioncharts folder are actually structured the way you think. (E.g., is there really a js/[insert name here].js file inside the fusioncharts folder?
If none of that solves your problem, try to take something that is working and gradually make it more and more similar to the files that aren't working. By figuring out at which point you go from a working setup to a not working setup, you may discover the problem.

If you are referring to a file with path: /ui/new-file.js
then,
1.In html file include
<script type="text/javascript" src="/ui/new-file.js"></script>
2.In server.js or app.js whichever you have, include
app.get('/ui/new-file.js', function (req, res) {
res.sendFile(path.join(__dirname, 'ui', 'login-file.js'));
});

Assuming you are using codeigniter, you can use base_url() function to include JS files in your codeignitor view template file.
<script src="<?php echo base_url(); ?>fusioncharts/js/fusioncharts.js" type="text/javascript"></script>
codeigniter default view template is called welcome_message.php and this file is located in application/view folder.
This is how I include js files in my codeigniter projects. Hope this will help.

In the html you can write *script** in the head or in the body, but not in your file js, delete this in fusionCharts.js
<script type=text/javascript>
In fusionCharts.js write only the function without the script

If you are developing locally, try clearing your cache.
Google Chrome likes to use the cached JavaScript files instead of the real ones.
Clearing your cache should resolve the issue.

Xml to js code problem

So i'm very new to xml to javascript so i thought I would learn from w3schools, but this site
http://www.w3schools.com/xml/xml_to_html.asp shows an example that I can't mimic locally. I copy/pasted the .js and downloaded the xml but I just get a blank screen!
It's working in there try it yourself but not for me? Do I need it on a server or something?

Yes, that code retrieves the XML data from a web server using AJAX. Since you don't have a server running locally, you can change the URL to point directly to the w3school's version:
xmlhttp.open("GET","http://www.w3schools.com/xml/cd_catalog.xml",false);
Alternatively, play around on their online version ;)

well i guess you have to add the example xml (cd_catalog.xml) to your file system. and you definitively have to access the html file on a server (apache i.e.)

First, ensure that both HTML file (with the Javascript block in it) and XML file are placed in the same directory.
Next, you probably need to place those files under your local web-server and open the HTML like this:
http://[local server host]/ajax.html
instead of opening the file directly from e.g. Windows Explorer:
C:\[path to the file]\ajax.html
For the latter case you'll get an "Access is denied" error.
-- Pavel

Are you running this under a web server or just creating a couple of text files and loading them in your browser?
The "GET" request this relies upon could possibly be failing.
Use Apache or another similar HTTP server and run the example as if it were hosted on the web.