feat(element): add support for dynamic module configuration

[gshokanov]

This pull request makes it possible to configure LazyElementsModule with dynamic values known only at runtime, while still allowing for AOT compilation. Implements functionality for #28. The API now supports two signatures:

• Current signature with static values:

const lazyElementOptions: LazyElementModuleRootOptions = {
    elementConfigs: [
        { tag: 'ba-header', url: 'https://example.com/header-component' }
    ]
};

@NgModule({
    imports: [
        LazyElementsModule.forRoot(lazyElementsConfig)
    ]
})

• New signature with dynamic factory:

export function lazyElementOptionsFactory(): LazyElementModuleRootOptions {
    return {
        elementConfigs: [
            { tag: 'ba-header', url: resolveUrl('ba-header') }
        ]
    };
}

@NgModule({
    imports: [
        LazyElementsModule.forRoot(lazyElementsOptionsFactory)
    ]
})

Please review and let me know what you think. I'll work on adding documentation later.

[codecov-io]

Codecov Report

Merging #29 into master will increase coverage by 0.19%.
The diff coverage is 71.42%.

@@            Coverage Diff             @@
##           master      #29      +/-   ##
==========================================
+ Coverage   85.86%   86.05%   +0.19%     
==========================================
  Files          30       30              
  Lines         290      294       +4     
  Branches       38       40       +2     
==========================================
+ Hits          249      253       +4     
  Misses         34       34              
  Partials        7        7

Impacted Files	Coverage Δ
...ents/src/lib/lazy-elements/lazy-elements.tokens.ts	100% <100%> (ø)	⬆️
...ents/src/lib/lazy-elements/lazy-elements.module.ts	80% <60%> (+3.07%)	⬆️

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[tomastrajan]

Hi @MagicCurlyHair !

Sorry for the late response, I think the idea to support that is great! The implementation looks a bit like too much, but I am not sure if it can be reduced to a bit less will explore it and let you know.

[gshokanov]

Hey @tomastrajan

I agree that it's far from being minimalistic. I spent quite some time on this issue and this is the only solution that I have come up with that doesn't break anything and seems to be working under all conditions. Maybe there is a better way, but I haven't found any.

[p-wunderlich]

I like this idea, any news on this? :)

[tomastrajan]

@pschalk @MagicCurlyHair will try to have a look soon

[tomastrajan]

@MagicCurlyHair @pschalk I had a look and I think we do not need this solution after conversation with @irekBudzowski as it can be achieved already today without complicating the library further...

The solution is to provide already available LAZY_ELEMENT_CONFIGS token as a multi: true provider with an useFactory function...

@NgModule({
    imports: [LazyElementsModule.forFeature({})],
    providers: [
        {
            provide: LAZY_ELEMENT_CONFIGS,
            useFactory: elementConfigsFactory,
            multi: true
         }
    ]
})
export class SomeFeatureModule {}

export function elementConfigsFactory() {
    // resolve config dynamically
}

The solution then would be to update the docs so it is clear how this can be achieved...

[gshokanov]

@tomastrajan great idea, I like it. This PR can be closed then

[tomastrajan]

So I have added docs which describe how this can be done.

Also, there was a little change to how the LAZY_ELEMENT_CONFIGS are processed internally to make sure that these extra LAZY_ELEMENT_CONFIGS provided direcly using multi: true provider are not lost. (see d0a9842 for more info)