I am a newbie in angular2 and want to know the purpose of following imports we do in our angular2 app.
<script src="node_modules/es6-shim/es6-shim.min.js"></script>
<script src="node_modules/systemjs/dist/system-polyfills.js"></script>
<script src="node_modules/angular2/bundles/angular2-polyfills.js"></script>
<script src="node_modules/systemjs/dist/system.src.js"></script>
<script src="node_modules/rxjs/bundles/Rx.js"></script>
<script src="node_modules/angular2/bundles/angular2.dev.js"></script>
<script src="node_modules/angular2/bundles/http.dev.js"></script>
so my questions regarding these imports are:
what are these imports for?
does the sequence of these imports metter?
are there any other useful imports that we must be aware of?
Thanks in advance.
I don't see any imports in your code sample. Its just including the files of various libraries into web page. If you read some of them one by one:
es6-shim.min.js - adds ES6 language features to browsers (full list)
Rx.js adds Observables library (GitHub RxJS)
http.dev.js - adds angular2 $http module to make requests
So you can google each of the names and figure out for yourself if that's applicable for your project.
More on modules and actual imports in ES2015/ES6 you can read here https://ponyfoo.com/articles/es6-modules-in-depth for example.
"useful imports that we must be aware of?"
Totally depends on your needs. By I assume angular2.dev.js and http.dev.js would be a good to start.
"does the sequence of these imports matter?"
Not now, but only if you're using proper module system so that browser can load missing parts before executing the blocks that depend on them. And also the loader file (system.js/require.js) should be in the first before all the other files.
Here are the details about what you specified in your script elements:
The two first files aren't necessary if you use TypeScript and have configuted ES5 output.
angular2-polyfills.js - Contains ZoneJS (to trigger change detection - see What is the Angular2 equivalent to an AngularJS $watch?) and reflect-metadata (to set metadata on objects from decorators)
system.src.js - SystemJS, the library that manages modules. In short when you use import and export in TypeScript the corresponding compiled code relies on it.
Rx.js - RxJS, a library that provides an implementation of Reactive Programming concepts. In short, it provides an implementArion of observables and their operators. EventEmitters, HTTP rely on this.
angular2.dev.js - Angular2 core bundle
http.dev.js - HTTP support of Angular2
Related
I'm thinking about developing an Excel add-in as described here.
Would that be possible with Svelte - and do you know of any guides/help if yes?
I have looked through the video here, and I'm about worried about the usage of webpack.
Well... let's break it down
Is it possible?
Short answer: yes
Long answer: the documentation clearly states that Excel add-in still uses jQuery for logic manipulations. If your question was about Angular or react it would probably be a hard NO since those frameworks use an engine that should be included as part of solution. This kind of dependencies when dealing with plugins development are pretty hard to implement and maintain as a function of time so it's better to use very lightweight, non-core dependencies instead. Since you are asking about svelte - it is "compiled" into a bundle that contains pure code (based on your app logic). So - as long as your app rely on the load event sequence described in the docs - you are good to go.
Do you really need Webpack?
Short answer: no
Long answer: svelte can be deployed using rollup instead - which is more suitable for micro-applications (such as yours). So, if you feel that webpack (somehow) is blocking your work pipeline - just use svelete default configuration with rollup and you are ready to go
Your workflow
Create a very simple svelte app (my suggestion - try to take the example in the docs and implement it using svelte)
Test it locally (just verify it works)
Build it (you should ended up with 3 files - 1 html file in public directory and 2 other files in public/build directory - 1 js file and 1 css file (both called bundle)
Here's the tricky part - the html file does nothing - just loading the css and js files. In your case - you don't really need it
Change the bundle.css file to Home.css file
Change the bundle.js file to Home.js file and put your app inside the add-in main function
'use strict';
(function () {
Office.onReady(function() {
// Office is ready
YOUR SVELTE APP CODE SHOULD BE PLACED HERE
});
})();
Pack your add-in and test it
Technical notes
If Excel blocks the creation of new elements (using dynamic injection) - this approach will NOT work (since your entire app is generated by your js file)
Please refer to this article for more information about packing your app
Try to make your app as lightweight and small-size as possible just to avoid the risk of exceeding the limits allowed for add-ins
I have a project which is a mix of new code and old libraries, some of which is based on JQuery and JQuery plugins. I'm facing some issues where some plugins are using the global object ($) to integrate, and other are doing require("jquery") or the equivalent. This appears to be fetching two different instances of JQuery.
Because of some existing code, I need the global object to be there. However, to support my newer code I want anything that requires or imports 'jquery' to be provided the window.jQuery object instead of trying to load an external module.
Can I do this with SystemJS?
Did you try the SystemJS-Adapter-Modules? Create a file jquery.js and reference the globally loaded jQuery function:
module.exports = window.jQuery;
When you import "jquery" you should get a reference to the already loaded jQuery function.
SystemJS-Adapter-Modules
I'm developing a GWT project at the moment and it's been up and running for a while. New functionality that is to be added require extensive testing, visualizing and simulating of a specific algorithm. I would like to export that specific algorithm so that I may call it directly from JavaScript and do some canvas magic.
How can I export a number of classes for direct use in JavaScript from a GWT project?
I've tried using the GWT exporter, following the Getting Started section closely.
I've noticed that my output directory contains a new generator class (TestClassExporterImpl.java) but the final JavaScript output contains no trace of my TestClass or the exported methods.
I'm sure I've made a mistake somewhere on the way or didn't understand the GWT exporter correctly.
Try to disable obfuscation, it will create the same names in Javascript as in the original Java code
I have created two separate add ons. One for getting input from the user and storing in simple-storage. In the other one the actual add on function. Both work fine. But when i merge these both main add on code in to a single main code they didn't work. So i wonder whether there can be two js files in "main" add on directory and is communication possible between them?I need one of the js in main directory to be able to access the simple-storage of the other js in the same main directory.
I'm really not sure what your overall goal is, please provide an example for a more specific answer. If you're using the Add-on SDK, only code in main.js will be run, but you can use commonJS modules to implement various features and use require to import them into main.js.
Please see the docs for more information on how the Add-on SDK works:
https://developer.mozilla.org/en-US/Add-ons/SDK
Does SAPUI5 load the libraries each time I call jQuery.sap.require("someLibrary")?
For instance if I am calling the above statement in multiple modules in my application, is "someLibrary" loaded multiple times also?
In case someone still considers to use jQuery.sap.require, be aware that it sends only synchronous XHRs which should be avoided.
The use of jQuery.sap.require is synchronous and considered as "bad practice" because syncXHR is deprecated by the Web Hypertext Application Technology Working Group. (Source: Modules and Dependencies)
Instead, the current best practice is to use sap.ui.define or .require for asynchronous module loading:
<!-- Enable asynchronous module loading in index.html (available since 1.58.2) -->
<script id="sap-ui-bootstrap" src="..." data-sap-ui-async="true" ...>
sap.ui.define([ // or .require
// modules to load
], function(/* modules available once loaded */) {
// ...
});
Source: Asynchronify Your App by Arnd vom Hofe. Note: anonymous sap.ui.define can be called only once at top-level.
Same as jQuery.sap.require, the API sap.ui.require([/*...*/]) fetches the modules also only once depending on their internal states.
For more information, please take a look at the topics under Modules and Dependencies.
Sync XHR is deprecated not only by the web platform generally, but will be also replaced by UI5 gradually with a new set of APIs.
Source: UI5 Evolution by Peter Muessig
Consequently, jQuery.sap.require and jQuery.sap.declare are now deprecated and will be removed in the next major UI5 version (aka. "Legacy-free UI5")!
The lib is only loaded once. You can find this information in the SDK
https://sapui5.hana.ondemand.com/sdk/#docs/guide/ModularizationConcept.html
Module Loading
As mentioned already, modules are loaded by calling function jQuery.sap.require with the name of a required module. The framework then checks whether the named module is loaded already. If so, the function simply returns. Otherwise it tries to load and execute the module synchronously. If any of these two steps fails, an exception is thrown and execution of the calling module thereby is disrupted.
When you call this function with some library, it checks that given library is loaded or not using associative array. If the library is loaded, then it returns null. And if the library is not loaded, then it loads the library using sjax call and after a success of the sjax call, it sets the library name as key into associative array.
The libraries are loaded once. This can be seen in the network tab in chrome developer tools.
Also check the documentation as pointed by cevou here:
https://openui5.hana.ondemand.com/#/topic/91f23a736f4d1014b6dd926db0e91070