Uncompressed jQuery file: http://code.jquery.com/jquery-2.0.3.js
jQuery Source code: https://github.com/jquery/jquery/blob/master/src/core.js
What are they doing to make it seem like the final output is not using Require.js under the hood? Require.js examples tells you to insert the entire library into your code to make it work standalone as a single file.
Almond.js, a smaller version of Require.js also tell you to insert itself into your code to have a standalone javascript file.
When minified, I don't care for extra bloat, it's only a few extra killobytes (for almond.js), but unminified is barely readable. I have to scroll all the way down, past almond.js code to see my application logic.
Question
How can I make my code to be similar to jQuery, in which the final output does not look like a Frankenweenie?
Short answer:
You have to create your own custom build procedure.
Long answer
jQuery's build procedure works only because jQuery defines its modules according to a pattern that allows a convert function to transform the source into a distributed file that does not use define. If anyone wants to replicate what jQuery does, there's no shortcut: 1) the modules have to be designed according to a pattern which will allow stripping out the define calls, and 2) you have to have a custom conversion function. That's what jQuery does. The entire logic that combines the jQuery modules into one file is in build/tasks/build.js.
This file defines a custom configuration that it passes to r.js. The important option are:
out which is set to "dist/jquery.js". This is the single
file produced by the optimization.
wrap.startFile which is set to "src/intro.js". This file
will be prepended to dist/jquery.js.
wrap.endFile which is set to "src/outro.js". This file will
be appended to dist/jquery.js.
onBuildWrite which is set to convert. This is a custom function.
The convert function is called every time r.js wants to output a module into the final output file. The output of that function is what r.js writes to the final file. It does the following:
If a module is from the var/ directory, the module will be
transformed as follows. Let's take the case of
src/var/toString.js:
define([
"./class2type"
], function( class2type ) {
return class2type.toString;
});
It will become:
var toString = class2type.toString;
Otherwise, the define(...) call is replace with the contents of the callback passed to define, the final return statement is stripped and any assignments to exports are stripped.
I've omitted details that do not specifically pertain to your question.
You can use a tool called AMDClean by gfranko https://www.npmjs.org/package/amdclean
It's much simpler than what jQuery is doing and you can set it up quickly.
All you need to do is to create a very abstract module (the one that you want to expose to global scope) and include all your sub modules in it.
Another alternative that I've recently been using is browserify. You can export/import your modules the NodeJS way and use them in any browser. You need to compile them before using it. It also has gulp and grunt plugins for setting up a workflow. For better explanations read the documentations on browserify.org.
Related
I am building a Sails.js application using sails 1.2.3, node 10.15. I want to include a javascript module in my api/helpers/* directory, without sails automatically using it to try to create a helper. I.e. I have javascript objects that use helpers and are used in a helper, but are not helpers themselves; as in this image, where the module 'rules' is imported into the create-rule helper and the objects exported by this module are used within the helper.
By default, sails tries to load each file in the helpers/* directory as a helper, and throws if the underlying implementation does not match that of a valid helper:
ImplementationError: Failed to load helper `create-rule/rules/foo/index` into a Callable! Sorry, could not interpret "index" because its underlying implementation has a problem:
------------------------------------------------------
• Missing the `fn` property.
------------------------------------------------------
Hoping someone can help out! Let me know if more info is needed. Thanks in advance!
I don't quite understand what you are trying to do. In my humble opinion I would grab all object constructors and placed them as a single file in api/services. That will make it automatically available in all controllers. I would not allow my object's methods to use helpers by them selves (I even think you can't, at least easily). Then when you need a helper to use your object, just pass it as parameter. Anyway, again, in my humble opinion; you are structuring your code to fit all inside /helpers and that will make it extremely hard to develop. Let assume you manage to make it work all inside /helpers, only you without exception, will be able to understand what it does or how it works. Doesn't seem as a good idea.
I am working on video.js library. I was trying to modify it, so that it uses a custom player instead of the HTML5 player.
So I replaced the function calls to play() etc with the calls to my custom player(say custFunc1()). These calls are defined in a separate javascript file: custPlayer.js.
So in my index.html file, I will first include the custPlayer.js file and then the built video.js file.
However the problem is that while building the video.js package using grunt, I get the error that custFunc1 is not defined and thus grunt is not able to create the video.js library.
Now I was able to find out from a colleague that adding
/* global custFunc1 */
at the beginning of the particular file in the video.js package from where I was calling custFunc1 resolves the issue. The grunt build succeeds and it works fine.
So what I want to know is:
How does this actually resolve the issue, since this is exactly like a comment in javascript, how does it treat this differently and understand that it indicating that the function definition will be present outside the library?
Is the word global some sort of keyword in javascript?
Are there other ways of achieving this apart from what I mentioned?
On a slightly different note, I wanted to ask if grunt is the rough equivalent of make ?
Your javascript is being linted as part of your grunt process, if you look at the root of your project folder you should see a file like .jshintrc or something along those lines (different depending on the linter).
Your current settings means that the linter is going through your .js files one at a time and if it comes across a variable or function from another files it's throwing the error your seeing. You can either turn off this check or add custFunc1 to an array of known global variables. In jshint you do it like so - https://github.com/gruntjs/grunt-contrib-jshint#jshintrc
{
"globals": {
"custFunc1": true
}
}
The globals will probably already be present in the file, so just add custFunc1: true to it.
Oh and to answer question 1 - the comment type syntax tells the linter to ignore it's settings for that current file, basically overriding the settings in the .jshintrc file.
2 - Yes it's a setting in jshintrc and your adding custFunc1 to it inside the file itself instead of globally in the .jshintrc file.
3 - Mentioned above.
4 - Never used maker but yes i believe its similar in that its a pre process tool
Is there any way I can include an external JS library in my pebble code?
Conventionally on a webpage I would do this in my head tags:
<script type='text/javascript' src='https://cdn.firebase.com/js/client/1.0.11/firebase.js'></script>
But in pebble, I am unable to do that since I am only using JS. So how can I include an external library for a JavaScript file.
At present, you cannot include external JS files.
If you're using CloudPebble, then the only way to do this is to copy and paste the content of the JS library files into your JS file.
If you're doing native development, you can modify the wscript file to combine multiple JS files into one at build time.
I think there's some confusion over Pebble.js vs PebbleKit JS (v3.8.1). Pebble.js is a fledgling SDK where eventually the programmer will be able to write pure JavaScript. It's still cooking so there's some functionality missing like the ability to draw a line or obtain the screen dimensions. The repo is a mix of C and JS sources where you can add C code to augment missing functionality but otherwise all your code lives in src/js/app.js or src/js/app/. Anyway, Pebble.js does support require.
I don't use CloudPebble but I got the impression that it either supports Pebble.js (and hence require) or is planning to. I think all this SDK boilerplate code would be hidden.
PebbleKit JS does not support require out of the box AFAIK. I've made a demo that ports require support from Pebble.js to PKJS. The summary of changes is:
Move your project's src/js/pebble-js-app.js to src/js/app/index.js.
Remove any ready event listener from src/js/app/index.js. index.js will
be loaded when the ready event is emitted.
Add src/js/loader.js from Pebble.js.
Add a src/js/main.js that calls require('src/js/app') on the ready event.
Update your wscript with the following
deltas.
When adding new modules, place them under src/js/app/ and require('./name') will work.
I've tried to cover this all in the demo's readme.
BTW, here's the official breakdown of all the different SDKs but it's a little confusing.
I am not sure if there have been changes since the above answer, but it looks like there is in fact a way to include additional resources while keeping things tidy. On the pebbleJS page, there is the following section with an some information on the subject.
GLOBAL NAMESPACE - require(path)
Loads another JavaScript file allowing you to write a multi-file project. Package loading loosely follows the CommonJS format. path is the path to the dependency.
You can then use the following code to "require" a JS library in your pebble project. This should be usable on both Cloud Pebble as well as native development.
// src/js/dependency.js
var dep = require('dependency');
You can then use this as shown below:
dep.myFunction(); // run a function from the dependency
dep.myVar = 2; // access or change variables
Update:
After some digging into this for my own, I have successfully gotten CloudPebble to work with this functionality. It is a bit convoluted, but follows the ECMAScript 6 standards. Below I am posting a simple example of getting things set up. Additionally, I would suggest looking at this code from PebbleJS for a better reference of a complex setup.
myApp.js
var resource = require('myExtraFile'); // require additional library
console.log(resource.value); // logs 42
resource.functionA(); // logs "This is working now"
myExtraFile.js
var myExtraFile = { // create a JSON object to export
"value" : 42, // variable
functionA : function() { // function
console.log("This is working now!");
}
};
this.exports = myExtraFile; // export this function for
// later use
I'm trying to convert a JavaScript-heavy page to use TypeScript, with RequireJS to manage the module dependencies.
The problem I've got is that, as well as the inter-dependencies between the TypeScript files, the page also depends on some common JavaScript files that are shared with other parts of the system, not yet converted to AMD.
Is it very dangerous to put non-AMD scripts in normal <SCRIPT> tags above the tag for Require, and just assume that they're loaded?
If that's a bad idea, what's a better way to handle this? Do I need to have AMD and non-AMD version of each script? Or do I need to convert all scripts so that they optionally call define()?
Recent versions of RequireJS allow you to pretend that the plain JS files are actually AMD modules that just return nothing.
The most recent version I tried - 2.1.4 - actually allows you to treat plain JS files like modules. Example:
require(
[
'path/to/module' // <- AMD module
,'path/to/plainjs' // <- actually a plain JS file
]
, function(module, plain){
// module will be per define in that file.
// plain will be 'undefined' type
}
)
You can just mix module-like refs to plain JS files freely. As long as they are loaded in the right order, they will update whatever globals they update and you get what you want. Example:
require(['js/underscore'], function(){
// nesting to insure Underscore, a prereq to BackBone
// completes loading before backbone starts
require(
[
'path/to/module' // <- AMD module
,'js/backbone' // <- actually a plain JS file
]
, function(module){
// module will be per define in that file.
window.BackBone // is available for you
}
)
})
Note, while RequireJS used to require that you add ".js" to the end of the plain JS files to indicate that they are plain JS, in the examples above you do NOT use ".js" This, extension-less module reference allows the module ID to follow paths and maps aliases, while ids with .js are treated as literal and are never translated.
You can manually include the additional scripts in script tags, but this could become the reason things always break for your team (someone forgot to add a particular script).
You can reference the require.d.ts definition from Definitely Typed and make direct calls to the require function rather than an import statement, which might make things more consistent for you.
I am currently maintaining a large number of JS files and the dependency issue is growing over my head. Right now I have each function in a separate file and I manually maintain a database to work out the dependencies between functions.
This I would like to automate. For instance if I have the function f
Array.prototype.f = function() {};
which is referenced in another function g
MyObject.g = function() {
var a = new Array();
a.f();
};
I want to be able to detect that g is referencing f.
How do I go about this? Where do I start? Do I need to actually write a compiler or can I tweak Spidermonkey for instance? Did anyone else already do this?
Any pointers to get me started is very much appreciated
Thanks
Dok
Whilst you could theoretically write a static analysis tool that detected use of globals defined in other files, such as use of MyObject, you couldn't realistically track usage of prototype extension methods.
JavaScript is a dynamically-typed language so there's no practical way for any tool to know that a, if passed out of the g function, is an Array, and so if f() is called on it there's a dependency. It only gets determined what variables hold what types at run-time, so to find out you'd need an interpreter and you've made yourself a Turing-complete problem.
Not to mention the other dynamic aspects of JavaScript that completely defy static analysis, such as fetching properties by square bracket notation, the dreaded eval, or strings in timeouts or event handler attributes.
I think it's a bit of a non-starter really. You're probably better of tracking dependencies manually, but simplifying it by grouping related functions into modules which will be your basic unit of dependency tracking. OK, you'll pull in a few more functions that you technically need, but hopefully not too much.
It's also a good idea to namespace each module, so it's very clear where each call is going, making it easy to keep the dependencies in control manually (eg. by a // uses: ThisModule, ThatModule comment at the top).
Since extensions of the built-in prototypes are trickier to keep track of, keep them down to a bare minimum. Extending eg. Array to include the ECMAScript Fifth Edition methods (like indexOf) on browsers that don't already have them is a good thing to do as a basic fixup that all scripts will use. Adding completely new arbitrary functionality to existing prototypes is questionable.
Have you tried using a dependency manager like RequireJS or LabJS? I noticed no one's mentioned them in this thread.
From http://requirejs.org/docs/start.html:
Inside of main.js, you can use require() to load any other scripts you
need to run:
require(["helper/util"], function(util) {
//This function is called when scripts/helper/util.js is loaded.
//If util.js calls define(), then this function is not fired until
//util's dependencies have loaded, and the util argument will hold
//the module value for "helper/util".
});
You can nest those dependencies as well, so helper/util can require some other files within itself.
As #bobince already suggested, doing static analysis on a JavaScript program is a close to impossible problem to crack. Google Closure compiler does it to some extent but then it also relies on external help from JSDoc comments.
I had a similar problem of finding the order in which JS files should be concatenated in a previous project, and since there were loads of JS files, manually updating the inclusion order seemed too tedious. Instead, I stuck with certain conventions of what constitutes a dependency for my purposes, and based upon that and using simple regexp :) I was able to generated the correct inclusion order.
The solution used a topological sort algorithm to generate a dependency graph which then listed the files in the order in which they should be included to satisfy all dependencies. Since each file was basically a pseudo-class using MooTools syntax, there were only 3 ways dependencies could be created for my situation.
When a class Extended some other class.
When a class Implemented some other class.
When a class instantiated an object of some other class using the new keyword.
It was a simple, and definitely a broken solution for general purpose usage but it served me well. If you're interested in the solution, you can see the code here - it's in Ruby.
If your dependencies are more complex, then perhaps you could manually list the dependencies in each JS file itself using comments and some homegrown syntax such as:
// requires: Array
// requires: view/TabPanel
// requires: view/TabBar
Then read each JS file, parse out the requires comments, and construct a dependency graph which will give you the inclusion order you need.
It would be nice to have a tool that can automatically detect those dependencies for you and choose how they are loaded. The best solutions today are a bit cruder though. I created a dependency manager for my particular needs that I want to add to the list (Pyramid Dependency Manager). It has some key features which solve some unique use cases.
Handles other files (including inserting html for views...yes, you can separate your views during development)
Combines the files for you in javascript when you are ready for release (no need to install external tools)
Has a generic include for all html pages. You only have to update one file when a dependency gets added, removed, renamed, etc
Some sample code to show how it works during development.
File: dependencyLoader.js
//Set up file dependencies
Pyramid.newDependency({
name: 'standard',
files: [
'standardResources/jquery.1.6.1.min.js'
]
});
Pyramid.newDependency({
name:'lookAndFeel',
files: [
'styles.css',
'customStyles.css',
'applyStyles.js'
]
});
Pyramid.newDependency({
name:'main',
files: [
'createNamespace.js',
'views/buttonView.view', //contains just html code for a jquery.tmpl template
'models/person.js',
'init.js'
],
dependencies: ['standard','lookAndFeel']
});
Html Files
<head>
<script src="standardResources/pyramid-1.0.1.js"></script>
<script src="dependencyLoader.js"></script>
<script type="text/javascript">
Pyramid.load('main');
</script>
</head>
It does require you to maintain a single file to manage dependencies. I am thinking about creating a program that can automatically generate the loader file for you based on includes in the header but since it handles many different types of dependencies, maintaining them in one file might actually be better.
JSAnalyse uses static code analysis to detect dependencies between javascript files:
http://jsanalyse.codeplex.com/
It also allows you to define the allowed dependencies and to ensure it during the build, for instance. Of course, it cannot detect all dependencies because javascript is dynamic interpretet language which is not type-safe, like already mentioned. But it at least makes you aware of your javascript dependency graph and helps you to keep it under control.
I have written a tool to do something like this: http://github.com/damonsmith/js-class-loader
It's most useful if you have a java webapp and you structure your JS code in the java style. If you do that, it can detect all of your code dependencies and bundle them up, with support for both runtime and parse-time dependencies.