@surface/custom-element/internal/directives/inject-directive.js

Provides support of directives and data binding on custom elements.

import { CancellationTokenSource } from "@surface/core";
import { tryEvaluateKeyExpressionByTraceable, tryObserveByObservable, tryObserveKeyByObservable, } from "../common.js";
import TemplateMetadata from "../metadata/template-metadata.js";
import { scheduler } from "../singletons.js";
export default class InjectDirective {
    constructor(template, descriptor, context) {
        this.cancellationTokenSource = new CancellationTokenSource();
        this.disposed = false;
        this.key = "";
        this.task = () => {
            this.disposeCurrentInjection();
            this.key = `${tryEvaluateKeyExpressionByTraceable(this.context.scope, this.descriptor)}`;
            const injectionContext = {
                customDirectives: this.context.directives,
                descriptor: this.descriptor,
                host: this.context.host,
                parentNode: this.context.parentNode,
                scope: this.context.scope,
                template: this.template,
            };
            this.metadata.injections.set(this.key, injectionContext);
            const action = this.metadata.placeholders.get(this.key);
            if (action) {
                action(injectionContext);
            }
        };
        this.template = template;
        this.descriptor = descriptor;
        this.context = context;
        this.metadata = TemplateMetadata.from(context.parentNode);
        template.remove();
        const listener = () => void scheduler.enqueue(this.task, "normal", this.cancellationTokenSource.token);
        this.keySubscription = tryObserveKeyByObservable(context.scope, descriptor, listener, true);
        this.subscription = tryObserveByObservable(context.scope, descriptor, listener, true);
        this.task();
    }
    disposeCurrentInjection() {
        if (this.key) {
            this.metadata.injections.delete(this.key);
            this.metadata.defaults.get(this.key)?.();
        }
    }
    dispose() {
        if (!this.disposed) {
            this.cancellationTokenSource.cancel();
            this.disposeCurrentInjection();
            this.keySubscription.unsubscribe();
            this.subscription.unsubscribe();
            this.disposed = true;
        }
    }
}