Require module from a root path - javascript

Suppose I've these directories:
'C:\\src' // Root path.
'C:\\src\\inner1' // Contain 'a.js'
'C:\\src\\inner2\\innermost' // Contain 'b.js'
So, if I do this in C:\\src\\inner1\\a.js:
require('inner2/innermost/b')
It must return the exported value from C:\\src\\inner2\\innermost\\b.js, but I do not want to use the executing script relative path, e.g.:
require('../inner2/innermost/b')
So, independently of the current script directory, I want to require a module from such root path.
How can I do it? There is no problem if I need to specify something at package.json.

Try this way
path = require('path');
path.resolve('../inner2/mostinner/b');

Related

Node converting relative path to absolute, not desired

I have the following issue, in the function sendDownload(downlodable ,objPathArray, responseObject) I am receiving the parameter objPathArray like this:
[{"pathToFile":"./REPORTS/portfolio/onDemand/Portfolio_report_HP_17.08.2021.xlsx","file":"Portfolio_report_HP_17.08.2021.xlsx"}]
The function:
function sendDownload(downlodable ,objPathArray, responseObject) {
if (downlodable) {
responseObject.download((objPathArray[0].pathToFile), (objPathArray[0].file))
console.log('HERE ' + JSON.stringify(objPathArray))
}
}
but when I call the function in my app I receive this error Error: ENOENT: no such file or directory, stat 'C:\Work\reporting-server\REPORTS\portfolio\onDemand\Portfolio_report_HP_17.08.2021.xlsx' and that's because Node is changing my relative path for the file in an absolute one.
What is the best option for me in order to solve this issue ?
Thank you~
Node.js must resolve the path to find the file.
If you give it a relative path then it has to start somewhere and that somewhere is the current working directory.
If you want it to read the file from somewhere else then resolve it to an absolute path yourself.
Generally speaking the tools to do this will be path.resolve and something to tell it where to start from such as a configuration file, environment variable, or the directory the module is in.

Resolve relative path relative to another path instead of current working directory

I have a Node.js module that looks like this:
module.exports = function()
{
// linked dependencies
this.dependency1 = 'dependency1/dependency1.exe';
this.dependency2 = 'dependency2/dependency2.exe';
this.dependency3 = 'dependency3/dependency3.exe';
}
I want developers to be able to easily edit the location of the dependencies relative to the module file itself. However, when using the module, the current working directory process.cwd() is usually not the same as the module directory, so those paths do not resolve correctly. path.resolve() only seems to work relative to the current working directory, and doesn't have any arguments to allow for a custom reference point/path.
I have been able to resolve the paths in the following way, but I find it ugly and cumbersome, and it should be easier than this:
this.ResolvePath = function(p)
{
var cwd = process.cwd();
process.chdir(path.dirname(module.filename));
var resolvedPath = path.resolve(p);
process.chdir(cwd);
return resolvedPath;
}
Is there a cleaner way to do this? I feel like path.relative() should hold the solution, but I can't find a way to make it work. Perhaps chaining together multiple path.relative()s could work, but I can't wrap my brain around how that would work right now.
why not just:
path.resolve(__dirname, p)
__dirname works a bit differently and returns the current modules path, which can then be joined easily with the relative path.

npm global packages: Reference content files from package

I'm in the process of building an npm package which will be installed globally. Is it possible to have non-code files installed alongside code files that can be referenced from code files?
For example, if my package includes someTextFile.txt and a module.js file (and my package.json includes "bin": {"someCommand":"./module.js"}) can I read the contents of someTextFile.txt into memory in module.js? How would I do that?
The following is an example of a module that loads the contents of a file (string) into the global scope.
core.js : the main module file (entry point of package.json)
//:Understanding: module.exports
module.exports = {
reload:(cb)=>{ console.log("[>] Magick reloading to memory"); ReadSpellBook(cb)}
}
//:Understanding: global object
//the following function is only accesible by the magick module
const ReadSpellBook=(cb)=>{
require('fs').readFile(__dirname+"/spellBook.txt","utf8",(e,theSpells)=>{
if(e){ console.log("[!] The Spell Book is MISSING!\n"); cb(e)}
else{
console.log("[*] Reading Spell Book")
//since we want to make the contents of .txt accesible :
global.SpellBook = theSpells // global.SpellBook is now shared accross all the code (global scope)
cb()//callBack
}
})
}
//·: Initialize :.
console.log("[+] Time for some Magick!")
ReadSpellBook((e)=>e?console.log(e):console.log(SpellBook))
spellBook.txt
ᚠ ᚡ ᚢ ᚣ ᚤ ᚥ ᚦ ᚧ ᚨ ᚩ ᚪ ᚫ ᚬ ᚭ ᚮ ᚯ
ᚰ ᚱ ᚲ ᚳ ᚴ ᚵ ᚶ ᚷ ᚸ ᚹ ᚺ ᚻ ᚼ ᚽ ᚾ ᚿ
ᛀ ᛁ ᛂ ᛃ ᛄ ᛅ ᛆ ᛇ ᛈ ᛉ ᛊ ᛋ ᛌ ᛍ ᛎ ᛏ
ᛐ ᛑ ᛒ ᛓ ᛔ ᛕ ᛖ ᛗ ᛘ ᛙ ᛚ ᛛ ᛜ ᛝ ᛞ ᛟ
ᛠ ᛡ ᛢ ᛣ ᛤ ᛥ ᛦ ᛧ ᛨ ᛩ ᛪ ᛫ ᛬ ᛭ ᛮ ᛯ
If you require it from another piece of code, you will see how it prints to the console and initializes by itself.
If you want to achieve a manual initalization, simply remove the 3 last lines (·: Initialize :.) and use reload() :
const magick = require("core.js")
magick.reload((error)=>{ if(error){throw error}else{
//now you know the SpellBook is loaded
console.log(SpellBook.length)
})
I have built some CLIs which were distributed privately, so I believe I can illuminate a bit here.
Let's say your global modules are installed at a directory called $PATH. When your package will be installed on any machine, it will essentially be extracted at that directory.
When you'll fire up someCommand from any terminal, the module.js will be invoked which was kept at $PATH. If you initially kept the template file in the same directory as your package, then it will be present at that location which is local to module.js.
Assuming you edit the template as a string and then want to write it locally to where the user wished / pwd, you just have to use process.cwd() to get the path to that directory. This totally depends on how you code it out.
In case you want to explicitly include the files only in the npm package, then use files attribute of package.json.
As to particularly answer "how can my code file in the npm package locate the path to the globally installed npm folder in which it is located in a way that is guaranteed to work across OSes and is future proof?", that is very very different from the template thingy you were trying to achieve. Anyway, what you're simply asking here is the global path of npm modules. As a fail safe option, use the path returned by require.main.filename within your code to keep that as a reference.
When you npm publish, it packages everything in the folder, excluding things noted in .npmignore. (If you don't have an .npmignore file, it'll dig into .gitignore. See https://docs.npmjs.com/misc/developers#keeping-files-out-of-your-package) So in short, yes, you can package the text file into your module. Installing the module (locally or globally) will get the text file into place in a way you expect.
How do you find the text file once it's installed? __dirname gives you the path of the current file ... if you ask early enough. See https://nodejs.org/docs/latest/api/globals.html#globals_dirname (If you use __dirname inside a closure, it may be the path of the enclosing function.) For the near-term of "future", this doesn't look like it'll change, and will work as expected in all conditions -- whether the module is installed locally or globally, and whether others depend on the module or it's a direct install.
So let's assume the text file is in the same directory as the currently running script:
var fs = require('fs');
var path = require('path');
var dir = __dirname;
function runIt(cb) {
var fullPath = path.combine(__dirname, 'myfile.txt');
fs.readFile(fullPath, 'utf8' , function (e,content) {
if (e) {
return cb(e);
}
// content now has the contents of the file
cb(content);
}
}
module.exports = runIt;
Sweet!

my config.js file is not being recognized

In my index.js file, I have const config = require('config'); written as one of the first lines.
And I have a file in my project folder called config.js
But I keep having my console tell my that it Cannot find module 'config'
My config file is this basically:
module.exports = {
'secretKey': 'mySecretCode12232',
'mongoUrl' : 'mongodb://localhost:27017/test'
};
This doesn't make any sense it should be working.
const config = require( path.join(__dirname, 'config'+'.js' ) );
I also have own function which loads atomaticaly from specified subdirectory at it's definition, it saves a lot of time.
When you don't provide any path selector in the require statement (eg. require('./config')), your code will search for the package named config and fail as it cannot find this specific one, as require will assume that it was the package name that was provided (and will start searching e.g. in your node_modules etc. - search path for it is not a trivial topic :) ).
If you want to require the module from another file, you have to provide a correct path to it, so assuming your config.js resides in the same catalog as your other file, the correct statement would be:
const config = require('./config'); // Extension can be omitted

node.js require from parent folder

I have the following structure:
-- node_modules
-- websites
---- common
------- config.js
---- testing
------- test.js
Inside config I have some variables set, which are being exported using module.export.
I am trying to retrieve those variables when running node test.js from config.js using the following codes:
var configData = require('./common/config.js')
var configData = require('../common/config.js')
None of them work. What can I do to retrieve the data from the other folder?
var configData = require('./../common/config.js');
./ is testing/
./../ is websites/
./../common/ is websites/common/
./../common/config.js is websites/common/config.js
from test.js:
const configData = require('../common/config');
You can safely omit '.js'.
As documentation say:
File Modules
If the exact filename is not found, then Node.js will attempt to load the required filename with the added extensions: .js,
.json, and finally .node.
.js files are interpreted as JavaScript text files, and .json files
are parsed as JSON text files. .node files are interpreted as compiled
addon modules loaded with dlopen.
A required module prefixed with '/' is an absolute path to the file.
For example, require('/home/marco/foo.js') will load the file at
/home/marco/foo.js.
A required module prefixed with './' is relative to the file calling
require(). That is, circle.js must be in the same directory as foo.js
for require('./circle') to find it.
Without a leading '/', './', or '../' to indicate a file, the module
must either be a core module or is loaded from a node_modules folder.
If the given path does not exist, require() will throw an Error with
its code property set to 'MODULE_NOT_FOUND'.
More info about how require() work here.
const cheerio = require('../node_modules/cheerio');
const request = require('../node_modules/request-promise');
const vl = require('../node_modules/validator');
const crypto = require('crypto');
const fs = require('fs');

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