unicorn-components/src/components/base/dynamic-container/dynamic-container.service.ts

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import { ComponentFactoryResolver, ComponentRef, Type, ViewContainerRef } from '@angular/core';

/**
 * Used to attach dynamic components to a container.
 * Extended by ModalService, ToastService... and so.
 *
 * @export
 * @abstract
 * @class DynamicContainerService
 */
export abstract class DynamicContainerService {
    defaultContainer: ViewContainerRef;

    constructor(private cmpFactoryResolver: ComponentFactoryResolver) { }

    setDefaultContainer(viewContainerRef: ViewContainerRef) {
        this.defaultContainer = viewContainerRef;
    }

    protected attachComponent(
        component: Type<any>,
        viewContainerRef: ViewContainerRef = this.defaultContainer
    ): ComponentRef<any> {

        if (!viewContainerRef) {
            throw new Error(`No container set.
                You can set one by default using modalService.setDefaultContainer(ViewContainerRef),
                Or manually at each modalService.createModal(...,..., ViewContainerRef)`
            );
        }
        return viewContainerRef.createComponent(
            this.cmpFactoryResolver.resolveComponentFactory(component)
        );
    }
}