0.2.0 overwrites class on fa-layers component

[ghost]

Describe the problem

Prior to 0.2.0 any classes on fa-layers were preserved. Now they are overwritten.

What did you expect?

Classes should not be overwritten.

Reproducible test case

https://stackblitz.com/edit/angular-z8v4ux-vvutjk

[toverux]

Yes! Same problem here.

FaLayersComponent has a HostBinding on class, and this takes control of the whole className string. Angular does not give different context to the components that are interested in the property.

This is discussed in angular/angular#7289, where there are a few proposed workarounds, the following ones seem good:

• using NgClass Need a way for a component to add CSS classes to host non-destructively angular/angular#7289 (comment)
• mixing the HostBinding with an Input : Need a way for a component to add CSS classes to host non-destructively angular/angular#7289 (comment)

[devoto13]

@toverux the latter approach looks good!

If anybody is willing to submit a PR I would be happy to review it. Otherwise I'll have time to work on this early next week. Please add tests to make sure these 3 syntaxes work correctly: [class]="my-class", [class.my-class]="true" and [ngClass]="{'my-class': true}" with the component.