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

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.

Related

Is there a way to cause the JS engine to load a .js file without explicitly importing something from it?

Maybe I'm trying to do something silly, but I've got a web application (Angular2+), and I'm trying to build it in an extensible/modular way. In particular, I've got various, well, modules for lack of a better term, that I'd like to be able to include or not, depending on what kind of deployment is desired. These modules include various functionality that is implemented via extending base classes.
To simplify things, imagine there is a GenericModuleDefinition class, and there are two modules - ModuleOne.js and ModuleTwo.js. The first defines a ModuleOneDefinitionClass and instantiate an exported instance ModuleOneDefinition, and then registers it with the ModuleRegistry. The second module does an analogous thing.
(To be clear - it registers the ModuleXXXDefinition object with the ModuleRegistry when the ModuleXXX.js file is run (e.g. because of some other .js file imports one of its exports). If it is not run, then clearly nothing gets registered - and this is the problem I'm having, as I describe below.)
The ModuleRegistry has some methods that will iterate over all the Modules and call their individual methods. In this example, there might be a method called ModuleRegistry.initAllModules(), which then calls the initModule() method on each of the registered Modules.
At startup, my application (say, in index.js) calls ModuleRegistry.initAllModules(). Obviously, because index.js imports the exported ModuleRegistry symbol, this will cause the ModuleRegistry.js code to get pulled in, but since none of the exports from either of the two Module .js files is explicitly referenced, these files will not have been pulled in, and so the ModuleOneDefinition and ModuleTwoDefinition objects will not have been instantiated and registered with the ModuleRegistry - so the call to initAllModules() will be for naught.
Obviously, I could just put meaningless references to each of these ModuleDefinition objects in my index.js, which would force them to be pulled in, so that they were registered by the time I call initAllModules(). But this requires changes to the index.js file depending on whether I want to deploy it with ModuleTwo or without. I was hoping to have the mere existence of the ModuleTwo.js be enough to cause the file to get pulled in and the resulting ModuleTwoDefinition to get registered with the ModuleRegistry.
Is there a standard way to handle this kind of situation? Am I stuck having to edit some global file (either index.js or some other file it references) so that it has information about all the included Modules so that it can then go and load them? Or is there a clever way to cause JavaScript to execute all the .js files in a directory so that merely copying the files it would be enough to get them to load at startup?
a clever way to cause xxJavaScriptxx Node.js to execute all the .js files in a directory:
var fs = require('fs') // node filesystem
var path = require('path') // node path
function hasJsExtension(item) {
return item != 'index.js' && path.extname(item) === '.js'
}
function pathHere(item) {
return path.join('.', item)
}
fs.readdir('./', function(err, list) {
if (err) return err
list.filter(hasJsExtension).map(pathHere).forEach(require) // require them all
})
Angular is pretty different, all the more if it is ng serve who checks if your app needs a module, and if so serves the corresponding js file, at any time needed, not at first load time.
In fact your situation reminds me of C++ with header files Declaration and cpp files with implementation, maybe you just need a defineAllModules function before initAllModules.
Another way could be considering finding out how to exclude those modules from ng-serve, and include them as scripts in your HTML before the others, they would so be defined (if present and so, served), and called by angular if necesary, the only cavehat is the error in the console if one script tag is not fetched, but your app will work anyway, if it supposed to do so.
But anyway, it would be declaring/defining those modules somewhere in ng-serve and also in the HTML.
In your own special case, and not willing to under-evalute ng-serve, but is the total js for your app too heavy to be served at once? (minified and all the ...), since the good-to-go solution may be one of the many tools to build and rebuild your production all.js from your dev js folder at will, or like you said, with a drag&drop in your folder.
Such tool is, again, server-side, but even if you only can push/FTP your javascript, you could use it in your prefered dev environment and just push your new version. To see a list of such tools google 'YourDevEnvironment bundle javascript'.
To do more with angular serve and append static js files under specific conditions, you should use webpack so the first option i see here is eject your webpack configuration and after that you can specify what angular should load or not.
With that said, i will give an example:
With angular cli and ng serve any external javascript files you wanna include, you have to put them inside the scripts array in the angular-cli.json file.However you can not control which file should be included and which one not.
By using webpack configuration you can specify all these thing by passing a flag from your terminal to the webpack config file and do all the process right there.
Example:
var env.commandLineParamater, plugins;
if(env.commandLineParamater == 'production'){
plugins = [
new ScriptsWebpackPlugin({
"name": "scripts",
"sourceMap": true,
"filename": "scripts.bundle.js",
"scripts": [
"D:\\Tutorial\\Angular\\demo-project\\node_moduels\\bootstrap\\dist\\bootstrap.min.js",
"D:\\Tutorial\\Angular\\demo-project\\node_moduels\\jquery\\dist\\jquery.min.js"
],
"basePath": "D:\\Tutorial\\Angular\\demo-project"
}),
]}else{
plugins = [
new ScriptsWebpackPlugin({
"name": "scripts",
"sourceMap": true,
"filename": "scripts.bundle.js",
"scripts": [
"D:\\Tutorial\\Angular\\demo-project\\node_moduels\\bootstrap\\dist\\bootstrap.min.js"
],
"basePath": "D:\\Tutorial\\Angular\\demo-project"
}),
]
}
then:
module.exports = (env) => {
"plugins": plugins,
// other webpack configuration
}
The script.js bundle will be loaded before your main app bundle and so you can control what you load when you run npm run start instead of ng-serve.
To Eject your webpack configuration, use ng eject.
Generally speaking, when you need to control some of angular ng-serve working, you should extract your own webpack config and customize it as you want.

Loading specific module from concatenated file using RequireJS

Trying to use the URI.js library in a project, but having trouble with RequireJS. URI's readme indicates that it works with requirejs - which is true when you're using the source - but not when using the minified/concatenated distribution file on its own - as you would in production.
Their build process scoops several libraries into a single .min file, and they all define themselves as modules.
No matter how I require that script, the only argument I receive is the first module in their distribution file (IPv6) which is not what I need.
Is there something trivial I'm missing?
<script>
require.config({
paths: {
urijs: 'dist/URI'
}
});
require(['urijs'], function(URI) {
console.log(URI);
});
</script>
Indeed the minified file cannot be used because it is not correctly built. All the define calls in it are anonymous whereas they should include the module name. If they had, you'd be able to use the minified file.
To get it to work, in the paths configuration, I've put urijs to point to the directory that contains all the individual .js files of the modules, and then I require URI.js as 'urijs/URI'. I let r.js minify it for distribution of my code.
I've installed it with npm but I've just checked with bower and the process should be exactly the same.

How to include minified library version in RequireJS optimization

My situation is as follows:
My project based on RequireJS.
I am using RequireJS Optimizer for to create a single JS file.
Some of the module use a certain third party library as a dependency.
The third party is NOT included in the optimized file (libName: empty
in the build config).
RequireJS is configured through var require = {} object which appears
on EACH PAGE, right above the RequireJS. The object defines a path to
the unminifed version of the library, among other things.
What i'd like to achieve:
Use the same config file in both development and production (the require={} object is included with tag on each page). During development I'd like modules to use the UNMINIFIED version of the third party.However, after optimization occurs, i would like all the modules to use the minified version of that third party.
I did think of a solution in theory, but it seems a bit messy and Im hopeful cleaner solution exists:
To have the runtime config point to unminified version
var require = {
paths:{
'thirdParty':'lib/thirdParty'
}
}
Create a module which execute (lets call it "PathRewrite" Module):
requirejs.config({
paths:{
'thirdParty':'lib/thirdParty.min'
}
})
In runtime configuration, define path to "PathRewrite" as empty
var require = {
paths:{
'thirdParty':'lib/thirdParty',
'PathRewrite':'empty'
}
}
In the build configuration file define a real Path to "PathRewrite" in order for it to be included in the "main" file (concatenated file after build).
Include "PathRewrite" as a dependency of a module which is executed first.
What I hope that will happen is that during dev, when optimized file is not used, PathRewrite is will not be used, hence the path to unminified third party in the runtime config will be used.
When the project is optimized, PathRewrite will be included and executed. According to RequireJS documentation, it is possible to run RequireJS configuration twice and the configuration will be appended/overwritten. PathRewrite execution will overwrite the path to "thirdParty" to minified, which will thus be used by all the modules.
Hopefully i've provided enough information. I'd be glad hear of other ways to get this done. Thanks in advance.
This topic appears to have been explored a bit in this answer:
Loading min.js files Generated by TypeScript with Require
Don't let the title discourage you. Typescript is not the core issue of the question being answered there. Unfortunately, the discussion reveals that the RequireJS optimizer may be the only way to get decent minification to work, as it seems incapable of selecting alternate paths properly.
Why don't you want to use inbuilt RequireJs optimizer? You may just include this option
optimize : "uglify2"
and all your and third-party code will be minified after concatenation. In this case you don't need to use minified versions of third-party libraries.

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'
}
]
}
},

require.js optimization: deep dependencies

I'm trying to optimize (i.e. build) my app which is dependent from ember-data. So as the path for ember-data I set this file https://github.com/emberjs/data/blob/master/packages/ember-data/lib/main.js but r.js includes only this particular file and omit it's dependencies. I thought maybe it's because of some kind of paths issue but I can't see any error messages in console.
Make sure that in your build file (the one you pass to r.js as a build config), you have:
findNestedDependencies: true
R.js is omitting so called "inline dependencies" by default so if you do have in your main.js i.e.
require(["sth"],function(){
require(["sthelse"]);
});
R.js will only load "sth" by assuming that "sthelse" should be loaded during runtime.
; )

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