Salient Soft

I posted about this kind of issue back in 2010 here.

Nowadays for my own project work I am happy to assume recent browsers, in particularly IE11 at least (noting that even this has been out a while now – it was released 4 years ago now so a reasonable start point).

This means that I am happy to use css Flex which makes this insanely simple compared to the old days. You just need display:flex;align-items:center in the container div and its content items will centre vertically.

I’ve just used this on a PrimeNG data list component to centre left thumbnails correctly in a list item with no issues.

Quite why we have had to suffer for so many years with arcane tricks (or risk ridicule by making it simple using tables for layout) is beyond me, but there we are.

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1/ Organising imports does not seem to happen automatically when it should. To organise imports for a given folder or the project, select the appropriate level in the navigator then hit Code/Optimise Imports or ctrl+alt+0 as detailed here.

2/ TSLint gives errors about double quotes in imports as it prefers single quotes in all the code (double quotes for html), but Webstorm uses double quotes by default when organising imports. You can change Webstorm to use single quotes as per this post here.

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I had a need to do this initially when implementing my own tab container component.

I wanted each tab to hold a parent reference to the container so that it could get the container’s active tab, to see if ‘it’ was the active tab.

There is significant discussion about this online. The parent can be injected directly via its class name, but this introduces tight coupling which is undesirable.

Another option discussed was the use of @Host in conjunction with injection, as per the angular docs here. In this case, the traversal of the injector  tree stops at the parent otherwise another compatible component could conceivably be injected from elsewhere.

My solution initially was to define parent and child interfaces which defined the interaction between them, as one would in Java. This decoupled them from each other. However, in Angular you cannot inject interfaces directly as they are not available at runtime. As I was already iterating the content children (the tabs) in the parent container, in the ngAfterContentInit() lifecycle hook (as this is the earliest point at which the content children are available), it was straightforward to manually assign the parent reference to each child via a method in the child interface. In this way the parent and children were decoupled – any parent supporting the container interface (used by the child) could host any children which used the child interface (used by the parent).

In the end I dumped the idea as it ended up a tad unwieldy – I only needed the child to detect if it was the active one and it was having to call a parent method to compare itself with the currently active tab to see if it was the one. This child element property was then used to ensure that only the content of the active tab was actually rendered. I finally just added a boolean active property on the child interface, and in the parent, when switching tabs, I cleared the active flag on the old active tab (if there was one) and set the active flag on the new active tab, as well as assigning a parent property for the currently active tab. Whilst this meant I was having to track the active flags correctly, I no longer had to handle parent references and parent method calls. This seemed less messy but it was a close call and either pattern in reality would be ok.

One point of note is that in Typescript, an interface can contain properties (as in fields in Java) as well as methods, so for example my interface for the child could contain active and default properties directly rather than having to additionally define isActive() and isDefault() methods.

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I had a use case where I was rolling my own simple tab container.

An interesting challenge of this use case was the fact that the tabs needed rendering in their own right, but also needed iterating separately in order to build the tab header bar.

This is an example use case where content markup might influence parent markup dynamically and in multiple areas, and that attributes of the content markup are used in parent markup.

To do this I used the @ContentChildren decorator to inject an array of the tabs into the parent tab container. I could then easily iterate the array in the parent markup to build the header bar with labels and icons declared in the content children. In addition, the content children were rendered in their own right with their own content in different ways using <ng-content select=”…”></ng-content>.

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Prime now use Font Awesome for icons. They do not appear to be listed in the PrimeNG documentation/showcase, but are listed in the PrimeFaces one and may therefore be found here.

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I was trying to allow a left div for a menu to have a percentage width, possibly with a fixed min-width.

I then wanted to add a right div which filled all the remaining space to the right, to form a content pane.

My initial attempts which failed were:-

1/ Float both divs left – this partly works e.g. if I gave 25% width to the left and 75% width to the right, i.e. I had to assign width. If I then gave a min-width to the left, the right div drops underneath when the min-width kicks in.

2/ Per this post here, I took the float out of the right div. Whilst it extended to fill the right hand space, it also filled the left hand space, and placing e.g. a PrimeNG toolbar in the right hand pane resulted in a mess where the height of the toolbar filled the whole height of both divs. This was all due to the interaction of the floated and non floated div – the non floated one just flowed around the left hand floated div, and its content was in fact also hiding underneath the right one. In fact the comments mention that the proposed solution in the post does not work exactly as I found.

Finally an interesting solution which did work is this post here. The right float is not floated but is set to overflow:hidden. This triggers a Block Formatting Context, which interacts with the float to fill the remaining space. The right div becomes a BFC which prevents sibling floats from intruding on them, and also prevents descendant floats from escaping. The post explains the details on this well.

This worked correctly, even when the min-width was used in conjunction with a percentage width for the left div. A plunker showing a simple example of the BFC may be found here.

In the end I abandoned this approach of rolling my own layout. I was using PrimeNG components, and PrimeNG comes with a Grid CSS layout component which does full responsive 12 column based layout. It is nestable, and adaptable automatically for different screen widths via media queries. It is also used internally for the PrimeNG components, so will play nicely with them and will be less prone to side effects. I note from the comments that Bootstrap responsive column layout does not work well with PrimeNG, so I stuck with PrimeNG as it is flexible and easy to use.

Another alternative for grid layout which is big in this area is Foundation, which is also reviewed and compared with Bootstrap here. Bootstrap may be found here. Both Foundation and Bootstrap are frameworks offering components and css/theming as well as grid layout so would likely fight with Primefaces as this post indicates. It looks like you may be able to just get the grid with Foundation by now, not sure with Bootstrap.

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Instructions as per here:-

Updating Angular CLI

If you’re using Angular CLI beta.28 or less, you need to uninstall angular-cli package. It should be done due to changing of package’s name and scope from angular-cli to @angular/cli:

npm uninstall -g angular-cli
npm uninstall --save-dev angular-cli

To update Angular CLI to a new version, you must update both the global package and your project’s local package.

Global package:

npm uninstall -g @angular/cli
npm cache clean
npm install -g @angular/cli@latest

Local project package:

rm -rf node_modules dist # use rmdir /S/Q node_modules dist in Windows Command Prompt; use rm -r -fo node_modules,dist in Windows PowerShell
npm install --save-dev @angular/cli@latest
npm install

Note that for a primeNg application I also had to reinstall the angular animations module:-

npm install @angular/animations

Failing to do this caused numerous errors on an ng serve due to the inability to reference the animations(!) :-

ERROR in E:/Dev/angular/places-admin/node_modules/@angular/platform-browser/animations/src/animation_renderer.d.ts (1,53):
Cannot find module '@angular/animations/browser'.

ERROR in E:/Dev/angular/places-admin/node_modules/@angular/platform-browser/animations/src/providers.d.ts (8,276):
Cannot find module '@angular/animations/browser'.

ERROR in Error encountered resolving symbol values statically.
Could not resolve @angular/animations/browser relative to
E:/Dev/angular/places-admin/node_modules/@angular/platform-browser/animations/index.d.ts.,
resolving symbol ?e in
E:/Dev/angular/places-admin/node_modules/@angular/platform-browser/animations/index.d.ts,
resolving symbol BrowserAnimationsModule in
E:/Dev/angular/places-admin/node_modules/@angular/platform-browser/animations/index.d.ts,
resolving symbol BrowserAnimationsModule in
E:/Dev/angular/places-admin/node_modules/@angular/platform-browser/animations/index.d.ts

ERROR in ./~/@angular/platform-browser/@angular/platform-browser/animations.es5.js

Module not found: Error:
Can't resolve '@angular/animations/browser' in
'E:\Dev\angular\places-admin\node_modules\@angular\platform-browser\@angular\platform-browser'
@ ./~/@angular/platform-browser/@angular/platform-browser/animations.es5.js 13:0-249
@ ./src/app/app.module.ts
@ ./src/main.ts
@ multi webpack-dev-server/client?
http://localhost:4200 ./src/main.ts

ERROR in ./~/primeng/components/accordion/accordion.js
Module not found: Error:
Can't resolve '@angular/animations' in
'E:\Dev\angular\places-admin\node_modules\primeng\components\accordion'
@ ./~/primeng/components/accordion/accordion.js 13:19-49
@ ./~/primeng/primeng.js
@ ./src/app/app.module.ts
@ ./src/main.ts
@ multi webpack-dev-server/client?
http://localhost:4200 ./src/main.ts

ERROR in ./~/primeng/components/calendar/calendar.js
Module not found: Error:
Can't resolve '@angular/animations' in
'E:\Dev\angular\places-admin\node_modules\primeng\components\calendar'
@ ./~/primeng/components/calendar/calendar.js 13:19-49
@ ./~/primeng/primeng.js
@ ./src/app/app.module.ts
@ ./src/main.ts
@ multi webpack-dev-server/client?
http://localhost:4200 ./src/main.ts

ERROR in ./~/primeng/components/confirmdialog/confirmdialog.js
Module not found: Error:
Can't resolve '@angular/animations' in
'E:\Dev\angular\places-admin\node_modules\primeng\components\confirmdialog'
@ ./~/primeng/components/confirmdialog/confirmdialog.js 13:19-49
@ ./~/primeng/primeng.js
@ ./src/app/app.module.ts
@ ./src/main.ts
@ multi webpack-dev-server/client?
http://localhost:4200 ./src/main.ts

 
It appeared that I did not need to reinstall primeng via npm install primeng –save. In fact although it initially ran without, I did reinstall this too as well as the animations.

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Update 30/5/2017

Re the comment below on the stylesheet link tags not being honoured in index.html, it may still be ok to do this when the css is somewhere under the assets folder, as webpack loads these. I hit this on the Learning Tree angular course in an exercise, course 2324 ex 2.1, and moving a css folder from the src level to under the assets folder solved the problem – prior to this I was getting net errors on all the stylesheets (interestingly the exercise was originally set up wrong, which proved useful when diagnosing this issue) . This therefore may still be an alternative in some cases to using angular-cli.json.

Original Post

This is pretty much covered here, but salient points/commands as follows:-

ng new places-admin –style=scss
cd places-admin
npm install primeng –save
npm install @angular/animations
npm install font-awesome –save
ng serve

• Note the use of –style=scss as the default is plain css.
• angular animations are used for angular 4
• font awesome is used and needs to be both installed as above and added as a dependency in package.json along with primeng (this was already done automatically when I looked).
• Note that you need to import either BrowserAnimationsModule or NoopAnimationsModule in addition to BrowserModule – the post above mentions this but does not actually do it in the sample code:-

import { BrowserModule } from '@angular/platform-browser';
import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
...

@NgModule({
declarations: [
…
],
imports: [
BrowserModule,
BrowserAnimationsModule,
FormsModule,
HttpModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }

Styles configuration issue

Per the setup instructions above I initially just configured the style sheets with link tags in index.html:-

<link rel="stylesheet" type="text/css" href="/node_modules/primeng/resources/themes/omega/theme.css" />
<link rel="stylesheet" type="text/css" href="/node_modules/primeng/resources/primeng.min.css" />
<link rel="stylesheet" type="text/css" href="YOUR_PATH/font-awesome.min.css" />

 

When I did this alone, the style sheets would not resolve at run time. Per some online post suggestions I tried various alternative path prefixes such as “/node_modules”, “./node_modules”, and “../node_modules” but none would resolve. When I looked in the chrome inspector I was getting 404s on all the style sheet loads. I checked the file system and all the referenced files were present under node_modules, but they were just not available to the web server/were not being served. It appears that this is a consequence of the way that angular-cli and webpack package up the application. I then tried adding the style references specifically to .angular-cli.json as per the instructions :-

"styles": [
  "../node_modules/primeng/resources/primeng.min.css",
  "../node_modules/primeng/resources/themes/omega/theme.css",
  "../node_modules/font-awesome/css/font-awesome.min.css",
  //...
],

This worked and the styles/theming did resolve correctly. In fact, the static link references were not used at all and could be removed.

When examining components which used the css with the Chrome inspector, the css rules were being taken from style blocks directly, so this was clearly a packaging issue.

For dynamic theme switching, it may therefore be necessary to move the themes under the app resources and use a dynamically changed <link> tag or similar to select the target theme – this is the way that the PrimeNG Showcase does its theme switching, and there is no evidence at present of any other theme switcher component.

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NativeScript is the newer kid on the block – some of its key differences are as follows:-

1. NativeScript uses its own XML based element tags which are compiled to actual native elements in the deployed application.
2. This means that your view templates do not use HTML or ‘normal’ css – the elements and attributes are different and therefore there is a learning curve here as you have to learn all the new markup.
3. Native feature access such as cameras etc. is easier with NativeScript – with Ionic, often plugins for Cordova are needed, however this appears set to improve fairly soon.
4. You still develop with Javascript or TypeScript, and you can use Angular for development. However, I am not clear on how all the dynamic features/specific attributes of Angular which target the HTML DOM will fit in and work with the NativeScript XML elements – I would expect there to be some compromises here on what you can do. NativeScript does support dynamic creation of elements, but I would not expect all this to work in the same way as adding dynamic html/changing innerHTML with Angular for example.
5. For development testing, you use an Android or IOS emulator e.g. under Windows. For android debugging, you can attach the Chrome developer tools to debug.
6. From the perspective of being a web developer, it looks like Ionic is easier and more familiar in use.
7. The key feature with NativeScript is that it does give you true native components, and the apps run faster as they are native. However the app size for download/install is also much larger.
8. It does correctly claim to support all its target platforms from a single code base – note that all the targets run native applications.
9. Therefore note that it does not create a web app of any kind. Therefore when support for Windows comes out sometime soon, this will be a native application running on Windows.

There are a number of pros and cons and no shortage of discussion on line, and the following posts do some in-depth comparison on this:-

http://pointdeveloper.com/category/nativescript/

http://pointdeveloper.com/nativescript-vs-ionic-framework-pros-cons/

http://stackoverflow.com/questions/40819520/hybrid-app-ionic-vs-nativescript

http://www.discoversdk.com/blog/ionic-2-vs-reactnative-vs-nativescript

https://www.thepolyglotdeveloper.com/2015/11/nativescript-vs-ionic-framework-should-you-switch/

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The landscape in this regard is pretty complex with a number of choices out there.

This StackOverflow post discusses the functionality and pros/cons of the alternatives and is helpful in gaining an idea of what they all actually do!

I was keen to pick tools that met my needs, especially re the ability to build apps from separate shared components, but did not want to over complicate things by using tools that I did not really need.

My conclusion from the above and all the comments is that for the moment all my need can be met by just sticking with Webpack (in conjunction with Angular CLI and Ionic CLI), and not venturing to use tools such as Gulp on top as I don’t really need to.

This is good as webpack is the standard for Angular and Ionic.

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