Hello I am just a noob and still learning. I have already downloaded and tried the chat tutorial of get-started part from socket.io. Now, I am again learning from another source. What's confusing me is that, do I always have to npm install in the beginning of every project after writing the dependencies in the package.json? Or is there any other way? I would be very glad if you could help me understand my confusion. Thank you!
Yes, before running, all dependencies must be installed. So you must run npm install.
When developing, you can use npm install --save <package_name> to install a dependency and automatically add it to package.json.
NPM means Node Package Manager. It is used to manage your dependencies to other node modules dynamically thanks to a configuration file called package.json. This way you can easily define the exact versions you need or a mask in order to always retrieve the stable ones for instance.
The command npm install allows to interpret your configuration file and then download the good versions (and this recursively).
Related
I have an interesting question. let us say that I'm going on a holiday where I don't have access to the internet. I happen to bring my laptop with me so that I can write some code. Me being an idiot or smart depending on perspective, I usually install my node modules using the global flag. I suspect that this adds the module locally.
My Question.
Is it possible to npm install a module locally installed into a new project without having access to the internet?
if so, what command does one run?
This is another way.
You will need to use the npm install command with the --offline flag, like this:
npm install --offline \<nameOfModule>
I've been working on a lot of different node.js projects. All of them have their own package.json file with their own needed packages. Every time I run node <mainfile>.js, npm installs all the packages to the project directory. Like so: C:/Users/me/Projects/<project-name>/node_modules.
This isn't a very big problem, but is there a way to make npm use/install to the global packages? Like in C:/Users/me/node_modules?
One of the advantages I could see this having is less storage being taken up, although it isn't a huge advantage.
I would assume that if it is possible, it would require you to add/modify something in the package.json file.
While looking into answers for this question, I've seen people saying that you should avoid installing packages globally. Can you also explain why this is a bad practice andy why I should avoid it?
Install Package Globally
NPM installs global packages into //local/lib/node_modules folder.
Apply -g in the install command to install package globally.
npm install -g express
To answer your other question
The obvious short answer is that your project depends on them. If your
project depends on a package, it should be documented in package.json
so that you can guarantee that it is installed when someone types npm
install. Otherwise, you’ll need to add extra steps in your README file
to inform anyone else who clones your project that they need to
install each of your global dependencies as well
Finally, even if someone installs the correct version of Browserify
for your project, they may be working on a different project that
requires a different version of that same tool, which would cause
conflicts. Several of your own projects might even use different
versions of Browserify because you updated it when you started a new
project and didn’t go back to make sure that earlier projects were
updated to work with the new version. These conflicts can be avoided.
You can only have one version installed globally. This causes problems if you have different projects that rely on different versions of a package.
Why not to install all packages globally
It's not really you shouldn't install a package globally it's more knowing what packages to install globally. The packages to install globally are ones that your project/application does not depend on.
How to identify a package that my project depends on
A package that your project is depended on is a package that your application could not run without like axios or express (an express API could not run without express installed or a web page that makes API requests with axios cant make those requests without axios) but something like http-server or minify is not needed to run the application so it can be installed globally.
Why is it important to have locally installed packages
It's important/good practice because if you are working with a group of developers or someone gets your work from Github they can just run npm install and get all the packages with out having to find all the packages them selfs.
How can I remove the node modules folder
You could technically globally install every package but I would sudjest not to. Node and many other developers know this is an issue that they have created a solution for in deno "the node killer".
I would recommend not installing all packages globally and if the node modules folder really annoys you try deno it fixes a lot of things that node developers hate.
I always thought that you should initialize npm first before installing any packages
npm init --yes
However I found out that I could just go straight to installing packages
npm i example-package
Then the package would be installed and package.json would be created at the same time.
Is there any reason I should be doing npm init first? Is it only required if I want to specify project details?
It is not required. You can install packages without, and everything will work.
npm init can do basically two things:
ask for basic project info to include in packages.json
create a specific type of project (for example React) by using npm init typeofproject
If you just want to use packages and don’t care about naming the project or using a template, just install packages.
npm init is there when you are installing the project very first time.
else you don't need to use npm init for installing any package
Well, kind of a late answer, but as far as I know (correct me if im wrong), one of the features is it gets set up with package.json which includes the dependencies list. That way, NPM can simply install the packages on the list (via the "npm init" if you have a situation that you want to clone the app into another machine), rather than copy pasting the whole project folder.
This isn't a direct answer to the question, but, if sheds some light at some point, why not.
I'm porting a node/Express app to Heroku, and it keeps crashing. The log first said, "Error: Cannot find module 'mongoose'" I then (re-)installed mongoose. Then it crashed with "Error: Cannot find module 'moment'"
I require mongoose, moment, etc. in my app. Isn't npm install by itself supposed to take care of the dependencies, or do I additionally have to add all these dependencies, one-by-one, to the package.json file, in addition to npm install? Tks!
In the older version of NPM (5.0.0 or earlier), you had to add --save as a flag to the npm install as:
npm i package-name --save
And it would add it to your package.json. As of 5.0.0 and later, it automatically adds it to the package file.
To answer your question, yes, you will have to add them one at a time for now. And keep in mind what I said before, because if you are using an older version of NPM, make sure you use --save when you are installing so you don't have to do extra work :-)
I need to use a package on npm, so I'm trying to learn how to use npm. The tutorials are fine, but I feel like they're assuming I know node.js, which I don't, and I'm having a hard time finding a tutorial for npm that doesn't also assume I know node.js. Do I need to learn node.js to use npm?
you don't need to know anything about node to use npm, its just a package manager. Install npm and then npm install all the packages you want. You will need to learn the npm toolchain, however, and it also helps to know which options are available for the various commands.
At the very least you should know the difference between installing a package globally and installing a package locally, i.e npm install -g vs. npm install respectively.