so far i've learned a bit about NodeJS. But now i want to write a huge enterprise app with it and i'm wondering how to setup the structure correctly? Coming from other languages like PHP and Java, i imagine, i would split my project in different NPM modules. For example #mybigproject/customer, #mybigproject/cart and #mybigproject/checkout and so on.
But those submodules would be installed in the node_modules folder of the application skeleton. How would i tell for example Express, that the template files are in the different module directories? Or for example i use TypeORM for data access. So each module would have it's own set of models. How do those models know the database configuration data, as it's only in the main application skeleton, or the other way around, how does the application skeleton should know where to find the models?
Don't use npm modules for different parts of your project.
This components is integral part of your project and usually depend on your global config / schema / routing / etc
Just put it in different files and require it where you need it.
You can get an idea for folders structure from projects like Sail.JS
Use npm modules if you writing some utility that going to serve you for different apps and you want an easy way to upgrade the utility code once for all your apps (or in case you want to share that utility as open source for all of us)
NPM can install your local folder as a dependency. (ref)
npm install <folder>:
Install the package in the directory as a symlink in the current
project. Its dependencies will be installed before it's linked. If
sits inside the root of your project, its dependencies may be
hoisted to the toplevel node_modules as they would for other types of
dependencies.
Your module keeps its original location after installed and a symlink is created as the same name of your module folder in the top level node_modules folder.
In these custom sub-modules, you can use __dirname and relative paths to locate you configuration files to feed to database or other data consumers.
But remember that, sub-modules often serve as utility functions for the main module. They should be independent from the project context.
Related
I am wondering what is the best way to keep archives/older versions of a specific module I am developing for nodeJS.
Say I have SampleModule v1.0.5 then later on I will be releasing SampleModule v2.0.0. I want to retain both versions in my node_modules folder since another app will only need SampleModule v1.0.5.
What is the best way to do this? Should I just have 2 diff folders: samplemodule105 and samplemodule200 then call something like require('samplemodule200') or require('samplemodule105')?
Also, so basically require() checks the folder name rather than the name and version inside a module's package.json right? This folder and name are only used to fetch the library via npm install?
I am building a RESTful API with the serverless framework to run on AWS (API Gateway + Lambda + DynamoDB). It's my first Node project and my first serverless production project and I have no idea how to structure it. So far I have the following
|--Functions
|-----Function1
|--------InternalModule
|-----Function2
|-----Function3
|--------InternalModule
|-----Function4
|--Shared
|-----Module1
|-----Module2
|-----Module3
|--Tests
|-----Functions
|--------Function1
|-----------InternalModule
|--------Function2
|-----------InternalModule
|--------Function3
|-----------InternalModule
|--------Function4
|-----------InternalModule
|-----Modules
|--------Module1
|-----------InternalModule
|--------Module2
|-----------InternalModule
|--------Module3
|-----------InternalModule
I keep my API endpoints (Lambda handlers) in Functions. Some of them have internal modules which they only use and there are some who use modules from Shared. I want to have unit tests for all my modules - inner and shared as well as API testing on the lambda functions. I am using mocha and chai and want to integrate everything in a pipeline which on a git push runs the linters and tests and if they are successful deploy the API to the appropriate stage. The problem is that in order to test each module I have to have chai as a local node module in every folder where I have a test file and reference the modules to be tested by a relative path. In most cases it looks really ugly because of the nesting. If I want to test an internal module from
Tests/Functions/Function1/InternalModule
and I require it on top of the test like so
require('../../../../Tests/Functions/Function1/InternalModule')
+ I have to install chai in every folder so it's reachable. The same goes for mocha and all the dependencies needed for the test and I haven't even mentioned configuration. The main idea I am now considering is weather or not I should bring all modules to a folder called modules and require them when needed - worst case
from Functions/Function1
require('../../Modules/Module1')
Also keep the test files in the module folder and run them inside, but that would require the assertion library installed in every folder. I've read about npm link and symlinks but I want to keep track of what dependencies each folder has so I can install them on the CI environment after the clean project is downloaded from GitHub where I can't do links (or I've got the whole concept wrong?)
If anyone can suggest a better solution I would highly appreciate it!
the way Node uses require is so much more than I thought!
First, Node.js looks to see if the given module is a core module - Node.js comes with many modules compiled directly into the executable binary (ex. http, fs, sys, events, path, etc.). These core modules will always take precedence in the loading algorithm.
If the given module is not a core module, Node.js will then begin to search for a directory named, "node_modules". It will start in the current directory (relative to the currently-executing Javascript file in Node) and then work its way up the folder hierarchy, checking each level for a node_modules folder.
read more here
I will try out Putting all modules in a separate folder each with it's own Folder prefixed with FunctionName_ so I know where each module is used, and the test file + package.json file. Then if I need a module I can require it from the functions with shallow nesting which would look not so bad:
from Functions/Function1
require('module-1');
with package.json
"dependencies":{
"module-1":"file:../../Modules/Function1_Module1"
}
and have a separate folder Shared where I keep the shared Modules.
I am still open for better ideas!
Node/NPM newbie with a front-end dev question. I understand one of the strengths of an NPM-type module is that its dependencies get installed within itself, in node_modules. Modules always have the code that they need, and outside libs don't conflict.
That said, seems like this would result in the client downloading the same lib+ver (say, jquery v.X) multiple times. What's the technique for specifying that a module needs a dependency but that it shouldn't package that code if the dependency is already available on the site/page? Does said technique involve parent modules that make the shared lib+ver available?
Or, should various front-end modules just re-download the same lib+ver that other modules on the page might have already downloaded?
The client will only grab files from that folder that are needed, so if it's linked in HTML once the client will only grab it once. NPM handles dependency duplicates automatically.
Having said that, normally you will want to only serve a static folder to the client without revealing your entire server structure. This can be achieved using:
app.use(express.static('server/public')
where 'server/public' is the directory relative to the server.js file that you want to serve. In this case, 'public' contains all my linked view files, stylesheets, JS files, etc. that are linked from the HTML pages. You don't need to move that module's dependencies there as well.
The downside to this is that you'd have to manually move dependencies into the public folder (I make a 'vendor' directory usually) and link from there. It's more work but it's much more efficient and safer in the long run.
NOTE: when using a static folder to serve files, your HTML links will be served from a relative path to that folder.
I'm working on a fairly large project where our code is split into separate modules. (Mostly because we're re-using this part over different services)
This becomes a problem when we're working across these different modules, it's a bit annoying to constantly push changes to github and run an npm install again in order to get these into a different project.
Is there a way to overwrite the location of a node module when in development? Basically while developing I just want to import the module from my local filesystem, while on production it want it to be imported from the git source.
You'll want to use npm link https://docs.npmjs.com/cli/link
This will allow you to create a direct link in your node_modules to a local version of your modules.
I am confused npm is a package manager, but Node.js has modules. So when you install or create your own... erhmm, module, package? Which word to choose over another and when?
Have a look at docs http://nodejs.org/docs/latest/api/modules.html :
In Node, files and modules are in one-to-one correspondence.
On the other hand package is a folder with a special package.json file in it. That file tells the interpreter how to load modules when you do require(folder);. In other words package is a collection of modules.
In Node, a single file is a module. It is a somewhat isolated entity from other parts of the program and by convention is usually written in a way where it can be run as an independent program (even if it doesn't do anything). On the other hand, a package in node is a larger entity. It is basically a complete program/library that serves some purpose. A package may consist of a single module file or hundreds of files.
The package is traditionally defined by "package.json" in the root directory of a package and it describes the creator's purpose and other things about the program.
If it has package.json/package.yaml at the top, and it is installable from npm registry, it is definitely a package.
If it's one simple javascript file (maybe a part of your package) written in CommonJS standard, it's a module.