Currently, I've created an NPM module and published it to NPM and included it in a separate project for use. I've performed NPM link so I don't have to publish every time I make a change and those updates are being reflected appropriately. However, I can't seem to debug the module itself. I've tried placing a debugger in the modules code within the node_modules directory and I've tried to place one in the actual module project, but to no avail. Is there a best practice for debugging an NPM module? If it helps, I'm using Visual Studio Code.
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I come from Java world and I'm used to code with Maven and Eclipse, which makes very easy to work with local dependencies as the IDE + M2Eclipse plugin is able to resolve dependencies from the workspace.
Now that I'm developing in JavaScript with NPM and VS Code, I find that you have to use manual options such as npm link + npm build --watch or npm pack + npm install <path> to work with local dependencies.
I'm developing an Angular application which codebase is split in different Git projects and npm packages, so we waste a lot of time testing local dependencies and also it is error prone.
I guess that this is caused by the different nature of JavaScript and Npm but, is there any plugin or option to ease local depevelopment in VS Code?
EDIT: I have seen this article about Yarn Workspaces and it looks like what I'm looking for... anything similar in npm? I see Lerna is an option but only for monorepos, I have separated Git repos for each library.
EDIT2: To clarify the problem, lets say I'm developing two Angular libraries, each on a different Angular workspace. Library A depends on library B. I use VS Code workspace to have these two Angular workspaces open at the same time and edit them together. If I change library B I have to build it and link it so that I can test the changes locally in library A before publishing. This is what "resolve dependencies from the workspace" solves in Eclipse + M2Eclipse in Java, the IDE just builds and links projects together. Thats what I'm looking for in VS Code + NPM in Angular.
EDIT3: New workspaces feature in NPM 7 looks promising, I will give it a try. Any thoughts about it?
I need to make some changes in one of my node module package. But the problem is that if I am changing any file inside node modules folder then the changes won't be available to the other developers as it won't be checked in. Others will install it via package.json.
Is there any way I can include the file in my application instead of node modules and will it be a good approach?
Kindly suggest if there is any other alternative.
You have three options
Send a PR to the actual npm package, if the change is like a bug fix or enhancement that aligns with the actual packages goal.
Fork the package repo, and make changes and use it in your project as a dependency, in case you are adding changes that does not align with the goals of the actual package
move the package code into your source code, and use it as source code rather than a package from npm
you can make a fork of the project, then inside your package.json add the dependency as
"package-name": "<your username>/<your repo name/probably same as package-name>#<branch>",
also you can install it using yarn/npm
npm install --save username/repo#branch-name-or-commit-or-tag
as show this link
this is all, run yarn o npm install and you'll get your changes, please make a PR to the original author and when this will be accepted you can return
I'm working on a set of JavaScript projects and some of these have dependencies between them. I've chosen JSPM as my package manager - which is all fine. But during development I want to have the most efficient frictionless way of working with this.
What is the best way for me to be able to have a dependency from one project to another in a totally transparent way - when I work on it locally, I get to just jump between projects without having to do any packaging or installation of packages and at the same time package information with its dependencies being what is expected to be for release (public package) and builds on the CI??
With NPM I could be doing npm link- anything similar I can be doing??
You could use jspm link
Running jspm link in a module will publish it into the locally global "link" repository.
Running jspm install --link will then install a project from the "link" repository.
The only functional difference between npm link is that (for the moment at least) jspm link will need to be run every time your local code changes. This can be automated with a watch task (see jspm-cli#481).
Is it ok to have a node.js project with no package.json? The ones I see on the internet all come with package.json
What is the effect of having no package.json?
How is package.json created in the first place? Is it created automatically? I am wondering why I do not have package.json
Fundamentally, package.json is a meta file for your application. It lists all the configuration of your application.
What is the effect of having no package.json?
Nothing as far as you're running all your code locally and have no requirement for deployment whatsoever.
Let's setup a scene for you to understand this better.
Imagine that you wrote a brilliant application using node. Now all the chicks in your surrounding want it to play with. It is so fantastic!
Now you want to give it to them and during the development process you `npm install`ed so many things that your project grows beyond 4TB size.
There is no data storage device available to ship that huge code base.
Then the girl of your dream said I want it and I want it now. So you begin searching for app deployment process for node applications.
That is where you stumble upon a magical thing called package.json.
So what you do is you list all your npm installed modules under dependencies property. Then you delete node_modulesfolder, add package.json and commit the entire damn thing in github. Even the .zip file is of 10MB
Then she gets the code.
Types in npm install && npm start (which will install all the dependencies from the package.json` and start your application)
If you have package.json however, that is where you specify all your dependencies.
Using --save flag of npm install
Example.
npm install express --save
How is package.json created in the first place? Is it created automatically?
You can manually create a text file and save it as package.json
OR
A more sophisticated way is to use the command
npm init
I am wondering why I do not have package.json
Me too! :)
You're most probably following a tutorial that doesn't emphasize on initial configuration of the project OR the author of those tutorials presume that the reader has all the fundamentals down to begin with.
It is created automatically if you write npm init.
Then, every package you add using npm install packagename --save will be added to the dependencies list.
You need package.json so that when you want to use your project on another machine you don't have to copy all node_modules, but only your .js files you have written, assets and package.json. You can then run npm install command and it will automatically download and install all the required modules (found in the list of dependencies inside package.json).
You can also manually create or edit it, but it's easier to add --save when installing a module so you don't have to worry about package versions and stuff like that.
Also if you want to create a npm package, an open source project or stuff other people will use, it's either required or the norm to have this package.json file describing your project.
package.json is npm file, if you don't use npm you will not have this file, npm is a great tool if you want to use external libraries in your project but if you don't need it (which is very not likely unless you are doing something very simple), you don't need package.json file too.
To generate package.json file initialize npm in your project using npm init
possible reason thus it exist is you maybe you enter a wrong command like npm i -y, you must initialize the project first, just enter a command npm init -y
Welcome.
Well, if you are running it on your local machine, it's fine. now to answer your last question, package.json is not created automatically.
the npm command npm init -y creates the 'package.json' file. It basically makes sharing your code and installing your codebase easier.
Just earlier, I posted my question:
https://stackoverflow.com/questions/28336443/how-to-not-put-my-js-files-in-user-myuser-for-node-js
I have a file, hello.js, located in /Users/MyUser/Desktop/Node/
I can see that my default directory is /Users/MyUser/
Okay, so I get that I need to change my working directory. What I have been able to find so far is to use >process.chrdir('/Users/MyUser/Desktop/Node/');
Cool, that works, but now when I get out of the REPL shell, the directory resets.
The person who responded to my question said that I needed to run >node init and later npm install <name of dependency> --save
My first question: I have ran >node init and see that I can create this package.json file, what does this do exactly?
Secondly: I was told that I need to add dependancies. Could someone please explain to me what this means in Node terms? Does a dependancy simply mean a folder that I want node to include? Do I want to add this Node folder on my Desktop to be able to run my scripts?
I am currently trying to go through the learnyounode courses, however I do not want to have to save all of these test files in my /User/MyUser directory, so any advice would be greatly appreciated.
Thanks
I have ran >node init and see that I can create
this package.json file, what does this do exactly?
npm init is used to create a package.json file interactively. This will ask you a bunch of questions, and then write a package.json for you.
package.json is just a file that handle the project's dependencies and holds various metadata relevant to the project[ project description, version, license information etc]
I was told that I need to add dependencies. Could someone please
explain to me what this means in Node terms?
Lets say you're building an application that is dependent on a number of NPM modules, you can specify them in your package.json file this way:
"dependencies": {
"express": "2.3.12",
"jade": ">= 0.0.1",
"redis": "0.6.0"
}
Now doing npm install would install a package, and any packages that it depends on.
A package is:
a folder containing a program described by a package.json file
a gzipped tarball containing (1)
a url that resolves to (2)
a # that is published on the registry with (3)
a # that points to (4)
a that has a "latest" tag satisfying (5)
a that resolves to (2)
If you need to install a dependency that haven't been included in package.json, simply do npm install <packageName>. Whether or not you want to include this newly installed package in package.json is completely your take. You can also decide how this newly installed package shall appear in your package.json
npm install <packageName> [--save|--save-dev|--save-optional]:
--save: Package will appear in your dependencies.
--save-dev: Package will appear in your devDependencies.
--save-optional: Package will appear in your optionalDependencies.
Does a dependency simply mean a folder that I want node to include?
Umm, partly yes. You may consider dependencies as folders, typically stored in node_modules directory.
Do I want to add this Node folder on my Desktop to be able to run my
scripts?
No, node manages it all. npm install will automatically create node_modules directory and you can refer to those dependencies with
require() in your .js files
var express = require('express');
Node REPL simply provides a way to interactively run JavaScript and see the results. It can be used for debugging, testing, or just trying things out.
process.cwd() points to the directory from which REPL itself has been initiated. You may change it using process.chdir('/path'), but once you close the REPL session and restart, it would always re-instantiate process.cwd() to the directory from which it has been started.
If you are installing some packages/dependencies in node project1 and think those dependencies can also be useful for node project2,
install them again for project2 (to get independentnode_modules directory)
install them globally [using -g flag]. see this
reference packages in project2 as
var referencedDependency = require('/home/User/project1/node_modules/<dependency>')
Simply doing process.chdir('/home/User/project1/node_modules/') in REPL and referencing as
var referencedDependency = require('<dependency>') in your js file wont work.
>process.chdir('/Users/MyUser/Desktop/Node/'); change the working directory only for that particular REPL session.
Hope it helps!
This has nothing to do with node.js but is rather inherent in the design of Unix (which in turn influences the design of shells on other operating systems).
Processes inherit values from their parent's environment but their environments are distinct.
That terse description of how process environments work has a sometimes unexpected behavior: you cannot change your parent's environment. It was designed this way explicitly for security reasons.
What this means is, when you change the working directory in a process and quits that process your shell's working directory will not be affected. Indeed, your shell's working directory isn't affected even when the process (in this case, node REPL) is running.
This exact question is often asked by people writing shell scripts wanting to write a script that CDs into someplace. But it's also common to find this question asked by people writing other languages such as Perl, Tcl, Ruby etc. (even C).
The answer to this question is always the same regardless of language: it's not possible to CD from another program/script/process.
I'm not sure how Windows handles it so it may be possible to do it there. But it's not possible on Unixen.