just like to add a short preface to this question - It may be a true issue of how Node functions, or it may be a fundamental misunderstanding on my part of how modules in Node work.
Recently, I've been working on a new project, specifically, a new Node module that requires some configuration via a .json file. I've had quite a few issues with this, being tested via linking the module to an Angular 2 (v5) project, and attempting to use the module in a service.
As I have the module set up right now, the configuration is loaded immediately as the module is initialized. It attempts to look for a config.json file, and read values from aforementioned file. I have this working, to an extent. I am able to require the file, read the file, and throw an error if the file is not found - but only in the same directory as the module's main file. The issue that I've come across is trying to determine how to find the path to the host project's root path - in this case, the Angular project. For example, say the absolute path to my module's root is /home/dev/angular2project/src/node_modules/module/. How can I determine the root path of the host, in this case /home/dev/angular2project/? What if the module has been installed globally?
I have attempted to use my weak understanding of the path module, paired with various searches of SO, to resolve this issue. I've tried using path.resolve(__dirname) to no avail path.resolve(process.cwd). This works well when debugging the module by itself. When attempted to be run from the Angular project, it simply returns / as the path, despite the actual root of the Angular project being home/dev/Desktop/angular2proj.
Related
Good day,
I am using protoc to generate pb files for nodejs. This step works fine. The proto files, and the code generated from them, are kept in a central location since different services will be using them (server and clients). If I copy these files into my project and use them, everything works fine. If I try requiring the files from the central location (which is outside of my project) I get an error
Error: Cannot find module 'google-protobuf'
The core of the question is, how do I require a file from outside of my project, that in turn requires a module from my project? Can this be done? I would have imagined that once the file was requires through relative pathing, it would become a part of the project, but this doesn't appear to be the case. Please help.
I have a fully functioning Electron App that uses node.js fs module to look at local files. I need to compare these files to files held on Dropbox. I have the Dropbox module all set up and running and have retrieved the content-hash for each file using the filesGetMetadata method and now I need to create a hash, in the same way, for each of my local files to compare to. I have found this code here: GitHub Repo written by Dropbox themselves, but being a relative newbie to Node.js and Electron I have only ever installed and 'required' node modules. This code just requires a js file (I tried to install the module, just in case!) and despite the js file I am implementing it on existing in the same directory as dropbox-content-hasher.js (like the example in the link) I can only get the error Uncaught Error: Cannot find module './dropbox-content-hasher' in my console. I've played with a few attempts at getting the right path but the error looks like it's still looking in the node_modules folder and I've no idea how to change this. Any help appreciated?!
I worked it out through trial and error... making the assumption from all my other requires that 'it' starts by looking in the node_modules folder, the following ended up working:
require('../src/js/dropbox-content-hasher.js');
Just thought I'd update this for anyone in my situation who doesn't quite know enough before embarking on a project!!
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!
I'm trying to fully understand how Typescript works in a Node.js project. To accomplish this I have created my own custom_modules folder with a separate #types folder underneath for my declarations while the actual implementation is under the custom_modules attempting to mimic the structure of node_modules. My goal is to make this module usable in the project non-relatively with separate declaration and implementation. I have been able to setup a project that compiles with this setup, but running it errors with:
Cannot find module 'foo'
The source is available here:
https://github.com/anorborg/learn-ts
The node_modules folder is a somewhat special case in how typings get handeled. This is a result of how nodejs works. Take a look at the [module-resolution] doucmentation (https://www.typescriptlang.org/docs/handbook/module-resolution.html), it describes more in depth how module resolution work in typescript.
But in short to answer your question: you can not use non-relative module paths in this way. Node will look for the file in node_modules at runtime, and will not find it there. The paths property in the tsconfig.json is there to solve problems that can occur in other cases, as when targeting RequireJS or SystemJS for example, but not when targeting node.
I used the command npm install firebase --save from the root of my project folder and a firebase folder was successfully added to my node_modules folder and the packages.json was also updated.
I also use typescript so I have a app.ts file where I try and do import Firebase = require("firebase");
However it doesn't work. I get red squiggles and error saying cannot find external module "firebase".
I have installed express and importing it in app.ts as well and that works fine, no errors.
I have tried to look through the firebase source but its minified and impossible to try and do any finding there, about what is exported and such.
Any ideas about what might be wrong and how I can fix it?
Three things:
You should download the Firebase type definition from Definitely Typed using NuGet, TSD, or some other method.
The Firebase definition on Definitely Typed doesn't seem to be written in an external module form. You may need to add the line export = Firebase; at the bottom of it.
TypeScript currently has odd default behavior with definition files (d.ts) that describe external modules written in JavaScript; it will search in each directory from the directory where the file is back to the root of the current drive looking for a .ts or .d.ts file with a name that matches the name of the thing you've imported. So your best bet is to move the Firebase.d.ts file to the root of the project. If you're interested in a bit more discussion on this, check out https://github.com/Microsoft/TypeScript/issues/2338 . They're working on it.
If you do those three things, it should work.