Is it possible to determine the directory where required scripts come from?
My ultimate goal is to...
// return the directory where `mysql` module is found
var mysqldir = requiredir('mysql')
if(fs.existsSync(mysqldir+"/README.md")){
console.log(fs.readFileSync(mysqldir+"/README.md").toString())
}
So I can have a handy reference for all these modules, and hopefully people in the enlightened future, will include module docs/cheatsheets intended to be accessed in this manner
required.resolve(...) may be what you're looking for:
function requiredir(id) {
return path.dirname(require.resolve(id));
}
Though, this will follow the main setting:
> requiredir('grunt')
.../node_modules/grunt/lib/
(Update: Documentation for the API isn't available anymore, so its use likely isn't supported.) Another option may be to use npm's view, though this is limited to registered packages:
npm.load({}, function (err) {
npm.commands.view(['mysql', 'readme'], true, function (err, readme) {
console.log(readme);
});
});
If you want to determine the absolute path of a module you can use require.resolve('module')
http://nodejs.org/api/globals.html#globals_require_resolve
You can extract the folder path by a regular expression
If you'd like to know programmatically, the module main directory which nodejs is using, this works
require.resolve('module_name').replace(/(.*node_modules.)(.*?)(\/)(.*)/, `$1$2`)
Example
For example, if you want to know where is the module main directory of module jquery which you're using in your nodejs code, the first part
require.resolve('jquery')
returns (in my case)
/home/jfolpf/autocosts/node_modules/jquery/dist/jquery.js
Pay attention that jquery.js is not stored in the module main directory; nonetheless
require.resolve('jquery').replace(/(.*node_modules.)(.*?)(\/)(.*)/, `$1$2`)
returns
/home/jfolpf/autocosts/node_modules/jquery
This takes into account that to resolve a module's path, node always seeks recursively for the folder named node_modules, as can be seen in documentation.
Related
I am trying to port a library from grunt/requirejs to webpack and stumbled upon a problem, that might be a game-breaker for this endeavor.
The library I try to port has a function, that loads and evaluates multiple modules - based on their filenames that we get from a config file - into our app. The code looks like this (coffee):
loadModules = (arrayOfFilePaths) ->
new Promise (resolve) ->
require arrayOfFilePaths, (ms...) ->
for module in ms
module ModuleAPI
resolve()
The require here needs to be called on runtime and behave like it did with requireJS. Webpack seems to only care about what happens in the "build-process".
Is this something that webpack fundamentally doesn't care about? If so, can I still use requireJS with it? What is a good solution to load assets dynamically during runtime?
edit: loadModule can load modules, that are not present on the build-time of this library. They will be provided by the app, that implements my library.
So I found that my requirement to have some files loaded on runtime, that are only available on "app-compile-time" and not on "library-compile-time" is not easily possible with webpack.
I will change the mechanism, so that my library doesn't require the files anymore, but needs to be passed the required modules. Somewhat tells me, this is gonna be the better API anyways.
edit to clarify:
Basically, instead of:
// in my library
load = (path_to_file) ->
(require path_to_file).do_something()
// in my app (using the 'compiled' libary)
cool_library.load("file_that_exists_in_my_app")
I do this:
// in my library
load = (module) ->
module.do_something()
// in my app (using the 'compiled' libary)
module = require("file_that_exists_in_my_app")
cool_library.load(module)
The first code worked in require.js but not in webpack.
In hindsight i feel its pretty wrong to have a 3rd-party-library load files at runtime anyway.
There is concept named context (http://webpack.github.io/docs/context.html), it allows to make dynamic requires.
Also there is a possibility to define code split points: http://webpack.github.io/docs/code-splitting.html
function loadInContext(filename) {
return new Promise(function(resolve){
require(['./'+filename], resolve);
})
}
function loadModules(namesInContext){
return Promise.all(namesInContext.map(loadInContext));
}
And use it like following:
loadModules(arrayOfFiles).then(function(){
modules.forEach(function(module){
module(moduleAPI);
})
});
But likely it is not what you need - you will have a lot of chunks instead of one bundle with all required modules, and likely it would not be optimal..
It is better to define module requires in you config file, and include it to your build:
// modulesConfig.js
module.exports = [
require(...),
....
]
// run.js
require('modulesConfig').forEach(function(module){
module(moduleAPI);
})
You can also try using a library such as this: https://github.com/Venryx/webpack-runtime-require
Disclaimer: I'm its developer. I wrote it because I was also frustrated with the inability to freely access module contents at runtime. (in my case, for testing from the console)
How can I include all files in nodeJS like
require('./packages/city/model/cities')
require('./packages/state/model/states')
require('./packages/country/model/countries')
like as
require('./packages/*/model/*')
same like grunt is loading files.
You can't (or at least you shouldn't)
In order to do this, you would have to overload node's native require function, which is highly inadvisable.
The CommonJS pattern might seem tedious to you, but it's a very good one and you shouldn't try to break it just because you saw shortcuts in other languages/frameworks.
By introducing some form of magic in your module, you suddenly change everything that programmers can (and should be able to) safely assume about the CommonJS pattern itself.
Due to one-to-one correspondence in node module loading system, it wont be possible natively, but would not be surprised if there is a package for this method.
Best you can do is create a index.js that loads modules present in directory and exports them as its own.
module.exports = function() {
return {
city : require('./city/model/'),
state : require('./packages/state/model/'),
country : require('./packages/country/model/')
}
}
you would have to load models in similary fashion in all three dirrectories as well.
I know that this solution is not what you are looking for but in my experirence, this method allows to better manage custom packages as you can add/remove features easily.
Node.js's require allows you to
load only one module at a time
load modules only in synchronous fashion.
That is how the module system works in Node.js. But if you want to have minimatch kind of matching functionality, you can roll one on your own, like this
var path = require("path"),
glob = require("glob");
function requirer(pattern) {
var modules = {},
files = glob.sync(pattern);
files.forEach(function(currentFile) {
var fileName = path.basename(currentFile);
fileName = fileName.substring(0, fileName.lastIndexOf(".js"));
modules[fileName] = require(currentFile);
});
return modules;
}
This depends on glob module, which allows you to use minimatch patterns to search files and then we require the found files, store them in an object and return the object. And this can be used like this
var modules = requirer('./packages/*/model/*.js');
console.log(modules.cities);
P.S: I am working on making this a public module already.
If I have a node.js application that has hundreds of files that reference a module (say underscore) and I want to replace that module with another (say lodash) then the obvious way to do this substitution would be a global name replace and switch out the modules in the package.json file.
Is there anyway to just change the module that a name refers to so that when node.js sees require('moduleA') it actually loads 'moduleB' instead? Now I know that this would cause naming hell because anyone working on the project would see require('moduleA') and wouldn't know that the real module being loaded was 'moduleB' so ultimately you'd probably want to go with the first solution. The use case that I'm thinking of is if you want to try a few alternatives for API compatible modules to measure your application's performance (for example) with each module.
If this is an on-going thing and you want to maintain the ability to programmatically switch between the options often, such as in tests:
Instead of using require("underscore"); throughout your codebase, require a local file instead like require("./lib/underscore");, and have that file conditionally re-export underscore or a different library:
if (global.USE_LODASH) {
module.exports = require("lodash");
} else {
module.exports = require("underscore");
}
If this is a one-off thing to try out an alternative library before making the decision to switch, and you want to do this test quickly first without find-and-replacing in all of your files:
Go inside your node_modules folder, delete or rename the underscore folder, and make a symlink named underscore to the replacement module's folder. I don't recommend this as a long-term solution: running npm install again will likely undo this hack, and most projects choose to avoid checking the node_modules folder into their source repository.
Try to use mock-require module.
I want to use a custom require() function in my application.
Namely I have node's standard require() and a custom one I wrote to require files starting from the root called rootRequire() which internally all it does is:
// rootRequire.js
var path = require('path');
var rootPath = __dirname;
global.rootRequire = function (modulePath) {
var filepath = path.join(rootPath, modulePath);
return require(filepath);
};
module.exports = rootRequire;
But even though rootRequire() internally uses node's require(), it does not pick up any files required through that method
Example:
require('rootRequire.js');
rootRequire('/A.js'); // server side it works, in the browser I get an error saying can't find module A.js
Perhaps, this will answer your question on why it is not working on browser.
Quoting the owner's comment: "Browserify can only analyze static requires. It is not in the scope of browserify to handle dynamic requires".
Technically, you are trying to load files dynamically from a variable with your custom require. Obviously, node.js can handle that.
In case of browserify, all requires are statically loaded and packaged when you run the CLI to build the bundle.
HTH.
What i recommend doing here is this:
First create a bundle to be required of anything you might use in rootRequire().
Something like browserify -r CURRENT_PATH/A.js -r CURRENT_PATH/B.js > rootRequirePackages.js
Then, in your webpage, you can include both rootRequirePackages.js and your regular browserified file.
Perhaps just use RequireJS ? It's simple to set up and relatively easy to use.
So, I have an app that is using requireJS. Quite happily. For the most part.
This app makes use of Socket.IO. Socket.IO is being provided by nodejs, and does not run on the same port as the main webserver.
To deal with this, in our main js file, we do something like this:
var hostname = window.location.hostname;
var socketIoPath = "http://" + hostname + ":3000/socket.io/socket.io";
requirejs.config({
baseUrl: "/",
paths: {
app : "scripts/appapp",
"socket.io" : socketIoPath
}
});
More complicated than this, but you get the gist.
Now, in interactive mode, this works swimingly.
The ugliness starts when we try to use r.js to compile this (technically we're using grunt to run r.js, but that's besides the point).
In the config for r.js, we set an empty path for socket.io (to avoid it failing to pull in), and we set our main file as the mainConfigFile.
The compiler yells about this, saying:
Running "requirejs:dist" (requirejs) task
>> Error: Error: The config in mainConfigFile /…/client.js cannot be used because it cannot be evaluated correctly while running in the optimizer. Try only using a config that is also valid JSON, or do not use mainConfigFile and instead copy the config values needed into a build file or command line arguments given to the optimizer.
>> at Function.build.createConfig (/…/r.js:23636:23)
Now, near as I can figure, this is due to the fact that I'm using a variable to set the path for "socket.io". If i take this out, require runs great, but i can't run the raw from a server. If I leave it is, my debug server is happy, but the build breaks.
Is there a way that I can lazily assign the path of "socket.io" at runtime so that it doesn't have to go into the requirejs.config() methos at that point?
Edit: Did some extensive research on this. Here are the results.
Loading from CDN with RequireJS is possible with a build. However, if you're using the smaller Almond loader, it's not possible.
This leaves you with two options:
Use almond along with a local copy of the file in your build.
Use the full require.js loader and try to use a CDN.
Use a <script> tag just for that resource.
I say try for #2 because there are some caveats. You'll need to include require.js in your HTML with the data-main attribute for your built file. But if you do this, require and define will be global functions, allowing users to require any of your internal modules and mess around with them. If you're okay with this, you'll need to follow the "empty: scheme" in your build config (but not in your main config).
But the fact remains that you now have another HTTP request. If you only want one built file, which includes the require.js loader, you'll need to optimize for only one file.
Now, if you want to avoid users being able to require your modules, you'll have to do something like wrap:true in your build. But as far as I can tell, once your module comes down from CDN, if it's AMD, it's going to look for a global define function to register itself with, and that won't exist because it's now wrapped in a closure.
The lesson I took away from all this: inline your resources to your build. It makes sense. You reduce HTTP requests, minify it all and get gzip compression. You don't expose your modules to the world and everything is a lot simpler. If you cache your resources properly you won't even need to worry about it.
But since new versions of socket.io don't like AMD, here's how I did it. Make sure to include the socket.io <script> tag before requirejs. Then create a requirejs module named socket.io with the following contents:
define([], function () {
var io = window.io;
window.io = null;
return io;
});
Set the path like so: 'socket.io': 'core/socket.io' or wherever you want.
And require it as normal! The build works fine this way.
Original answer
Is it possible that you could make use of the path config fallbacks specified in the RequireJS API? Maybe you could save the file locally as a fallback so your build will work.
The socket.io GitHub repository specifies that you can serve the client with the files in the socket.io-client package's dist/ directory.