Develop Reference

What is the use for the special "public" folder in a Meteor app?

I'm currently using Meteor and trying to learn more about the framework. In the documentation about special directories the following is said about the public/ special directory:
All files inside a top-level directory called public/ are served as-is to the client. When referencing these assets, do not include public/ in the URL, write the URL as if they were all in the top level. For example, reference public/bg.png as <img src='/bg.png' />. This is the best place for favicon.ico, robots.txt, and similar files.
My question is: since I refer to files inside of public/ directory as if they were located in the root folder of my application, what's the different between putting the files in the public/ folder and in the root folder? Or is it just for organization sake?
Also the documentation I quoted above makes some examples using assets (some pngs and favicon.ico) and no JavaScript or HTML files. Am I able to put some JavaScript code in there and then import them in another file by referencing as if this code was located in the root of my app? Or is the public/ directory somewhat made only for assets?
I failed to find any docs that explains what is done to files inside this directory in detail (I only found what I quoted above). So if any documentation of that kind is available it would help a lot!

My question is: since I refer to files inside of public/ directory as if they were located in the root folder of my application, what's the different between putting the files in the public/ folder and in the root folder? Or is it just for organization sake?
Just because you can reference or "import" a file from public/ doesn't mean it functions in the same way to how a normal file import would work. Files located in public gets served as is without being minified/run through the Meteor pipleline. Second, these files are accessible to the client which makes sense given how'd import them without preceding slashes and keep them mostly to serve stuff like favicon and what not.
So in a sense, such files within public are made available within relation to your client bundle/code whilst not being a part of them, get it?
This way of serving assets isn't unique to Meteor, even React has a public directory.
Also the documentation I quoted above makes some examples using assets (some pngs and favicon.ico) and no JavaScript or HTML files. Am I able to put some JavaScript code in there and then import them in another file by referencing as if this code was located in the root of my app? Or is the public/ directory somewhat made only for assets?
AFAIK, you can have files of any type in public but since
It's served as is to the client, meaning it's exposed to the public
It doesn't get minified (i.e being part of the final application build code)
You're advised to not have any of the application code within this directory.

The Public folder is how you serve your static files, when you put a file in your root folder it will not be sent to the client by default and you can't use it in your css, when you put that file (say an image) in your public folder you can use it from the css and refer to it as if it was in your root folder, so if I put a.jpg in the public folder I can use url(/a.jpg) in my css, that won't work if a.jpg is simply in your root folder, that's what the docs mean when they say it's served as if it was the root folder.

unlike in Rails, Meteor initiatives don’t have a rigid document structure and you are quite a whole lot free to prepare your projects as you want. a few folder names but have unique which means, and documents within them will be dealt with in a different way.
consumer
files here will be loaded at the client simplest. files in that folder don’t need things like Meteor.isClient.
server
Loaded on the server best, duh! No need for Meteor.isServer whilst files are in that folder, the client won’t see these files.
public
This directory is for property like photographs. on your initiatives, you reference stuff in the public folder as if they have been in the root folder. as an example, when you have a report: public/nude.jpg, then for your app you include it with .
personal
files only available at the server facet thru the assets API.
checks
documents in there received’t be loaded anywhere and are used for checking out your app.
lib
documents in that folder are loaded earlier than whatever else, which makes it the best listing to vicinity the distinct libraries used on a undertaking.

Why path in <script> src, starting with single slash results in error?

I have this project structure:
/root
/static
script.js
page.html
This code:
<html>
<head>
<script src="/static/script.js"></script>
</head>
<body>
...
</body>
</html>
results in:
Loading failed for the <script> with source “file:///static/script.js”.
Why is that? I would expect it to search for static folder in current directory (i.e. root).

In this particular case the error is produced, because I have just opened page.html in a browser on my machine (i.e. I have not served it via server), thus / is interpreted as local machine's root. If I have served the project, then / would be interpreted as project's root, and there would be no error.
A little more elaborate explanation/illustration.
Given this structure:
/root
/static
script.js
page.html
Here are what different paths (in page.html) will refer to:
/ — root directory, it might mean /root, but also might mean the root of current environment (see explanation at the beginning of this answer)
./ — current (the one where page.html resides) directory, it just so happens that it is /root in this case
it is worth mentioning that ./ can be omitted altogether, when referencing some file in current directory; so ./static/script.js is equivalent to static/script.js
I have derived understanding needed for this answer, from:
Aayush's answer to current question
this answer, to another question of mine
comments to this answer

The error is there because there is no such file in your system's root directory.
This can easily be solved by serving your /root folder and accessing the page.html via that server.
You can find a list of static file servers Here.
Going with Node.js's http-server.
Open a terminal in your '/root' directory and run the following commands:
npm install -g http-server
http-server -p 8000
Then you can access your page.html file at http://localhost:8000/page.html

If you have any directory into your root folder and your js file into that then you have to mention path only with folder name then file name like:
folder-name/filename.js
because into web browser there is no need to add forward slash into starting of file path
browser so it by self

serving static content in code structure generated by yeoman for angular fullstack

I am following the code structure generated by yeoman for angular fullstack.
I want to include a script called core.js in file called app.html.
<script src="core.js"></script>
I do not see express.static anywhere in this for serving static files.
I tried using it but it did not help.
It can not locate it and gives 404.
How do I get around this ?
It had happened before as well but I could get around it by using express.static and serving files from location pointed by it.
It did not help this time though.
Update:
I have app.html in folder called Music. In same folder, I have a sub folder called js where I have placed my core.js file that is to be included in app.html. I tried to access it using absolute as well as relative path but did not help and still gives 404.

In angular, the scripts go in the relevant subfolder of /scripts. Either in /controllers, /services/, /directives, etc. You then reference them in your html as such:
<script src="scripts/controllers/core.js"></script>
As for express.static, express is a NodeJS wrapper for HTTP. So that will be the service you create that lives on some Node server remotely. express.static allows the Node server to deliver static content files from the file set at the remote server. It does not go in your angular application.

What is the difference between JS files in dist/ folder and the one in root?

I am totally new to NodeJS and I wonder what's the difference between those two.
For example, in this project (https://github.com/fikriauliya/hipku), we have index.js and dist/hipku.js. They are similar except the last line:
module.exports = publicMethods; vs return publicMethods;
I guess dist/hipku.js is generated from index.js? How is it generated and why does it need to be generated?

Things in the dist folder are usually the product of building from index.js in this case. You'll notice it gets minified, and that folder would eventually be used on production sites. If you look at the package.json file, you'll notice that index.js is the main file, so if you're doing any edits, that would be the place to do so.

It depends on how you want to use this package, in browser or server side.
server side
index.js is the entry of NPM package. When you do require('hipku'), actually NodeJS locates the file module node_modules/hipku and run index.js ends up with the object adhere to module.exports
browser
Just load dist/hipku.js into your browser by <script>, it will register hipku into your global namespace, then you can use it's API.

ajax call to a local csv file

The folder structure is:
HOME\htmlhelp\wwhelp\wwhimpl\js\scripts
HOME\auxi\
I can read a csv file (located in the HOME\htmlhelp dir) from a js file located in the HOME\htmlhelp\wwhelp\wwhimpl\js\scripts dir using the following:
var file_path="../../../../../htmlhelp/rule_mapping.csv";
However, the same js file (from the same location) cannot read the same csv file in the HOME\auxi\ directory!
Am using the path as var file_path="../../../../../auxi/rule_mapping.csv";
It throws an "NS_ERROR_DOM_BAD_URI: Access to restricted URI denied" error. I have checked the file permissions and stuff but no luck.
Any help would be appreciated.

The problem lies within:
var file_path="../../../../../htmlhelp/rule_mapping.csv";
It's not possible to traverse up to paths out of the root directory where the document is located.
Assuming you work under UNIX (Linux/Mac), one solution would be to create a symbolic link on the root directory of the document, such as (executing from the scripts directory):
ln -s ../../../../../htmlhelp/rule_mapping.csv rule_mapping.csv
And changing the file_path to:
var file_path="./rule_mapping.csv";
I hope this helps!