NodeJS 'Require' loading library in coffeescript, empty object in Javascript - javascript

I've come across an interesting problem in NodeJS that pops up now and then at work, and I haven't been able to figure it out.
I've written a back-end in CoffeeScript, which I then compile with grunt-contrib-coffee into Javascript in a ~/bin directory. I also include a library that I privately host on Bitbucket with the appropriate private keys, and install through npm. This library too is written in coffeescript.
Usually I'm able to include this library in Javascript without any headaches, using a simple require just like I would for any other library. However, occasionally one of the servers that's using the back-end gets updates, and it stops working. When I go check the error, it's always the same - 'require' passes, but instead of loading the actual library in JavaScript, it returns an empty object ({}). Running the code in coffeescript still works, but regardless of what I do - recompile, reinstall all dependencies, remove and clone the repository, the problem persists.
I've run out of ideas of what it might be myself, so I'm hoping that someone here has come across the problem before and might be able to point me in the right direction.
In the library package.json:
{
"name": "graph-engine",
"main": "./lib/graph"
}
In the library's graph.coffee
class Graph
constructor: () ->
# Perform init
module.exports = Graph
Then in the app's package.json:
{
"graph-engine": "git+ssh://git#bitbucket.org:<team>/graph-engine.git"
}
Finally, in the app itself:
GraphEngine = require "graph-engine"
engineInstance = new GraphEngine()
This works fine in coffeescript, but when compiling the app using grunt with the following setup for grunt-contrib-coffee:
coffee:
glob_to_multiple:
expand: true
flatten: false
cwd: 'src'
src: ['**/*.coffee']
dest: 'bin'
ext: '.js'
It fails to load the library correctly when running the compiled application, instead returning an empty object. Again, I'd like to emphasise that this does not always happen, and as such I didn't include any code or json files as I believed that it was unrelated.

Although the exact reason for the randomness of the behaviour eludes me to this day, I have found that it is related to these libraries being written in CoffeeScript.
It seems that depending on the load order, occasionally third party libraries would register coffee script and my own libraries would load correctly, whereas other times these libraries would load after my own libraries had loaded, resulting in an inability to load coffeescript. Therefore, the solution turned out to be fairly straightforward - register coffeescript. This can be done by putting the following at the start of the node.js app:
require('coffee-script/register')
Refer to the documentation for further information.

Related

Make pdf.js 1.5 and require.js play nice together

In my project I have long used require.js together with the pdf.js library. Pdf.js have until recently been putting itself on the global object. I could still use it in my requirejs config by using a shim. The pdfjs library will in turn load another library called pdf.worker. In order to find this module the solution was to add a property to the global PDFJS object called workerSrc and point to the file on disk. This could be done before or after loading the pdfjs library.
The pdfjs library uses the pdf.worker to start a WebWorker and to do so it needs the path to a source file.
When I tried to update the pdfjs library in my project to a new version (1.5.314) the way to load and include the library have changed to use UMD modules and now everything get's a bit tricky.
The pdfjs library checks if the environment is using requirejs and so it defines itself as a module named "pdfjs-dist/build/pdf". When this module loads it checks for a module named "pdfjs-dist/build/pdf.worker". Since I have another folder structure I have added them to my requirejs config object with a new path:
paths: {
"pdfjs-dist/build/pdf": "vendor/pdfjs/build/pdf",
"pdfjs-dist/build/pdf.worker": "vendor/pdfjs/build/pdf.worker"
}
This is to make the module loader to find the modules at all. In development this works great. When I try to use the requirejs optimizer in my grunt build step however, it will put all of my project files into one single file. This step will try to include the pdf.worker module as well and this generates an error:
Error: Cannot uglify2 file: vendor/pdfjs/build/pdf.worker.js. Skipping
it. Error is: RangeError: Maximum call stack size exceeded
Since the worker source needs to be in a single file on disk I don't want this module to be included.
So I've tried two different config-settings in the requirejs config.
The first attempt was to override the paths property in my grunt build options:
paths: {
"pdfjs-dist/build/pdf.worker": "empty:"
}
The second thing to test is to exclude it from my module:
modules: [{
name: "core/app",
exclude: [
"pdfjs-dist/build/pdf.worker"
]
}]
Both techniques should tell the optimizer not to include the module but both attempts ended up with the same error as before. The requirejs optimizer still tries to include the module into the build and the attempt to uglify it ends up with a RangeError.
One could argue that since the uglify step fails it will not be included and I can go about my bussiness, but if the uglify step should happen to start working at a new update of pdfjs - what then?
Can anyone help me figure out why the requirejs config won't just exclude it in the build step and how to make it do so.
I found out what the core of my problem was and now I have a way to solve the problem and make my build process to work. My build step in grunt is using grunt-contrib-requirejs and I needed to override some options in the config for this job.
I didn't want the pdf.worker module to be included in my concatenated and minified production code.
I didn't want r.js to minify it only to later exclude it from the concatenated file.
I tried to solve the first problem thinking that it would mean that the second problem also should be solved. When I figured out the two were separate I finally found a solution.
In the r.js example on github there is a property named fileExclusionRegExp. This is what I now use to tell r.js not to copy the file over to the build folder.
fileExclusionRegExp: /pdf.worker.js/
Second, I need to tell the optimizer to not include this module in the concatenated file. This is done by overriding the paths property for this module to the value of "empty:".
paths: {
"pdfjs-dist/build/pdf.worker": "empty:"
}
Now my grunt build step will work without errors and all is well.
Thanks to async5 for informing me about the bug with uglify and the pdf.worker. The workaround is applied in another grunt task that uglify the worker and copies it into the build-folder separately. The options object for the grunt-contrib-uglify task will need this property in order to not break the pdf.worker file:
compress: {
sequences: false
}
Now my project works great when built for production.

How do I fix Webpack from mangling my code in production?

I'm building an application using BitcoinJS, and have found that using the -p flag causes webpack to mangle certain parts, breaking the ability to produce transactions.
I was advised to use noParse with alias in the config, which made the problem worse (the entire application would not load at all).
So far I have not found any workaround other than turning off production (which leaves all sorts of strange things in the javascript file, including my local development paths).
Example project available here (with install instructions, and how to reproduce): https://github.com/Someguy123/example-webpack-issue
EDIT/UPDATE: #bebraw has provided a working solution, which is available on the fixed branch in the example project if anyone else wanted to see it in action.
The problem is that Uglify mangles too much by default in your case. As per bitcoinjs-lib instructions, you need to exclude certain names like this:
plugins: [
new webpack.optimize.UglifyJsPlugin({
mangle: {
except: [
'Array', 'BigInteger', 'Boolean', 'Buffer',
'ECPair', 'Function', 'Number', 'Point'
]
}
})
]
Use webpack instead of webpack -p after configuring the plugin.
It will make the resulting bundle a little larger, but it will work.
Another alternative would be to generate the bundle separately for bitcoinjs-lib elsewhere and then consume that instead. You would have to take mangling into account there as well, but it would keep your project a little neater.

What's the best way to concatenate vendor js files?

In my Angular JS app, I'm using a lot of third party packages, mainly maintained via Bower.
When I use Grunt to concatenate all of them into one mega file, I'm getting errors when I load my page, for example that
Uncaught ReferenceError: angular is not defined and
GET http://localhost:8080/theproj/v4/dist/app/bootstrap.css.map 404 (Not Found)
What is the best way to properly concatenate all these files to ensure that everything loads in the right order and doesn't cause problems?
First issue: A lot of times third party libraries must be loaded in a particular order. That looks like like it's the source of your first issue. Something is trying to use angular and it's getting loaded before the angular code. You should refactor your grunt task to use a pre-defined order for third party libraries.
Second issue: You probably are missing the .map file. This is a file used by Chrome dev tools to show you the original source for the css (sass or less). Either provide the map file, or delete the reference to it from bootstrap.css. Or just ignore the error, it's only an error when you have chrome dev tools open, and doesn't actually affect your application.
For the issue of the correct order for your javascript files, i had that problem in a larger project where noone really had a clue which was the correct order.
Luckily we found that the Google Closure Compiler does exactly this: https://github.com/google/closure-compiler
You give it all your js files and it analyzes them all and concatenates them in order
$ java -jar compiler.jar --js_output_file=out.js in1.js in2.js in3.js ...
There is even a grunt plugin for the connection: https://github.com/gmarty/grunt-closure-compiler
'closure-compiler': {
frontend: {
closurePath: '/src/to/closure-compiler',
js: 'static/src/frontend.js',
jsOutputFile: 'static/js/frontend.min.js',
maxBuffer: 500,
options: {
compilation_level: 'ADVANCED_OPTIMIZATIONS',
language_in: 'ECMASCRIPT5_STRICT'
}
}
},
Another way would be to change your javascripts into AMD or CommonJS modules, this way you don't have to worry about the correct order. RequireJS (http://requirejs.org/docs/start.html) is a possibility for AMD for example or Webpack (http://webpack.github.io/) ...or many many others.

node.js load javascript library client side

I am fairly new to Node.js and I want to load a few javascript files in the browser but I can't seem to find anywhere how I can simply get libraries to be loaded inside the browser.
So, my question is, how would I be able to load javascript libraries client side with Node.js?
I'm fairly new to node as well, but I've been using browserify to deal with node packages. There are a quite a few node packages that won't work in a browser - if they will work in a browser they will usually say it in their description.
Browserify is really easy to use - you just require() a module just as you would when writing a non-browser script (as far as I can tell). When you're ready to test the script on a browser, you just run
browserify input.js -o output.js
and it pulls all of the dependencies from your require()'s into output.js, so then your require()s actually reference what you want it to.
--Updated for new comment--
As I see in your answer, you are talking about node.js packages? I am
talking about standalone random javascript libraries (so, for example
just one of my own js files that I want to load client side). Can you
also load random javascript libraries with browserify? (I googled a
bit but can't figure that out)
Yeah, you can do that; although I'm afraid I can't help you with the technicalities of it (like I said, new to it myself). Here's an example:
Bar.js (my library)
module.exports = bar; //tells node what to export in this file
var bar = {
message: function(msg) {
console.log(msg)
}
}
Foo.js (my script)
var bar = require('./bar');
bar.message("foo"); //logs "foo" to console
And keep in mind that require() refers to a file. So Bar.js would need to be in the same directory as Foo.js. If Bar.js was in a different folder, you would just do require('./folder/bar'). To tie it all together, you would run browserify on Foo.js, and it would automatically grab Bar.js' contents.
There are a lot of different ways you can define exports, so you'll need to google around to see exactly how to do it for how your lib is formatted. But that's the gist of it.

how to minify js files in order via grunt-contrib-uglify?

I have a directory like below:
/folder/b.js
/folder/jQuery.js
/folder/a.js
/folder/sub/c.js
I want to minify all these js files in one js file in order:
jQuery.js -> a.js -> b.js -> c.js
Q:
1.How can I do it via grunt-contrib-uglify?(In fact, there are lots of files, it is impractical to specify all source filepaths individually)
2.btw, How can I get unminified files when debug and get minified single file when release and no need to change script tag in html(and how to write the script tag)?
Good questions!
1) Uglify will reorder the functions in the destination file so that function definitions are on top and function execution on bottom but it seems that it will preserve the order of the function executions.
This means that the function jQuery runs to define its global functions will be put first if you make sure jQuery is mentioned first in Uglify's config in the Gruntfile.
I use this config:
uglify: {
options: {
sourceMap: true
},
build: {
files: {
'public/all.min.js': ['public/js/vendor/jquery-1.10.2.min.js', 'public/js/*.js'],
}
}
}
2) I don't think there is one definite way to accomplish this. It depends on what web framework, templating framework and what kind of requirements you have. I use express + jade and in my main jade layout I have:
if process.env.NODE_ENV === 'production'
script(src='/all.min.js')
else
script(src='/js/vendor/jquery-1.10.2.min.js')
script(src='/js/someScript.js')
script(src='/js/otherScript.js')
In my package.json I have:
"scripts": {
"postinstall": "grunt"
},
This means that when I run npm install on deploy (on Heroku) grunt is run to minify/concat files and when the app is started with NODE_ENV=production the minified client side javascript is used. Locally I get served the original client side javascripts for easy debugging.
The two downsides are:
I have to keep the two lists of script files in sync (in the Gruntfile and in the layout.js) I solve this by using *.js in the Gruntfile but this may not suite everyone. You could put the list of javascripts in the Gruntfile and create a jade-template from this but it seems overkill for most projects.
If you don't trust your Grunt config you basically have to test running the application using NODE_ENV=production locally to verify that the minification worked the way you intended.
This can be done using the following Grunt tasks:
https://github.com/gruntjs/grunt-contrib-concat concatenates
files
https://github.com/gruntjs/grunt-contrib-uglify minifies
concatenated files
EDIT
I usually run all my files through a Grunt concatenation task using grunt-contrib-concat. Then I have another task to uglify the concatenated file using grunt-contrib-uglify.
You're probably not going to like this, but the best way is to define your js source files as AMD modules and use Requirejs to manage the order in which they load. The grunt-contrib-requirejs task will recurse your dependency tree and concatenate the js files in the necessary order into one big js file. You will then use uglify (actually r.js has uglify built-in) to minify the big file.
https://github.com/danheberden/yeoman-generator-requirejs has a good example gruntfile and template js files to work from.
EDIT
I've recently started using CommonJS modules instead of AMD since it's much closer to the ES6 module spec. You can achieve the same results (1 big complied+concatenated js file) by running commonjs modules through Browserify. There are plugins for both grunt and gulp to manage the task for you.
EDIT
I'd like to add that if your site is written using ES6 that Rollup is the best new concatenating package. In addition to bundling your files, it will also perform tree shaking, removing parts of libraries you use if included via an import statement. This reduces your codebase to just what you need without the bloat of code you'll never use.
I don't think you can do this with the uglify task alone, but you have a multitude of choices which might lead to your desired outcome.
A possible workflow would be first concatenating (grunt-contrib-concat) the files in order into one single file, and put this concatenated file through uglify. You can either define the order for concat in your Gruntfile, or you use on of those plugins:
First one would be https://github.com/yeoman/grunt-usemin, where you can specify the order in your HTML file, put some comments around your script block. The Google guys made it and it's pretty sweet to use.
Second one would be https://github.com/trek/grunt-neuter, where you can define some dependencies with require, but without the bulk of require.js. It requires changes in your JS code, so might not like it. I'd go with option one.
I ran into the same issue. A quick fix is just to change the filenames - I used 1.jquery.min.js, 2.bootstrap.min.js, etc.
This might be only remotely related to your question but I wanted something similar. Only my order was important in the following way:
I was loading all vendor files (angular, jquery, and their respective related plugins) with a wildcard (['vendor/**/*.js']). But some plugins had names that made them load before angular and jquery. A solution is to manually load them first.
['vendor/angular.js', 'vendor/jquery.js', 'vendor/**/*.js]
Luckily angular and jquery handle being loaded twice well enough. Edit: Although it's not really the best practice to load such large libraries twice, causing your minified file unnecessary bloat. (thanks #Kano for pointing this out!)
Another issue was client-js the order was important in a way that it required the main app file to be loaded last, after all its dependencies have been loaded. Solution to that was to exclude and then include:
['app/**/*.js', '!app/app.js', 'app/app.js']
This prevents app.js from being loaded along with all the other files, and only then includes it at the end.
Looks like the second part of your question is still unanswered. But let me try one by one.
Firstly you can join and uglify a large number of js files into one as explained by the concat answer earlier. It should also be possible to use https://github.com/gruntjs/grunt-contrib-uglify because it does seem to have wildcards. You may have to experiment with 'expand = true' option and wildcards. That takes care of your first question.
For the second part, say you joined and uglified into big-ugly.js
Now in your html you can add following directives:
<!-- build:js:dist big-ugly.js -->
<script src="js1.js"></script>
<script src="js2.js"></script>
<!-- etc etc -->
<script src="js100.js"></script>
<!-- /build -->
And then pass it through the grunt html preprocessor at https://www.npmjs.com/package/grunt-processhtml as part of your grunt jobs.
This preprocessor will replace the entire block with
<script src="big-ugly.js"></script>
Which means that the html file with be semantically equivalent - before and after the grunt jobs; i.e. if the page works correctly in the native form (for debugging) - then the transformed page must work correctly after the grunt - without requiring you to manually change any tags.
This was #1469's answer but he didn't make it clear why this works. Use concat to put all js files into one, this module does this in the order of file names, so I put a prefix to the file names based on orders. I believe it even has other options for ordering.
concat: {
js: {
options: {
block: true,
line: true,
stripBanners: true
},
files: {
'library/dist/js/scripts.js' : 'library/js/*.js',
}
}
},
Then use uglify to create the minified ugly version:
uglify: {
dist: {
files: {
'library/dist/js/scripts.min.js': [
'library/js/scripts.js'
]
},
options: {
}
}
},
If your problem was that you had vendors which needed to be loaded in order (let's say jquery before any jquery plugins). I solved it by putting jquery in its own folder called '!jquery', effectively putting it on top of the stack.
Then I just used concat as you normally would:
concat: {
options: {
separator: ';',
},
build: {
files: [
{
src: ['js/vendor/**/*.js', 'js/main.min.js'],
dest: 'js/global.min.js'
}
]
}
},

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