class HTMLImportElement extends HTMLTemplateElement {

    get src(){
        return new URL(this.getAttribute("src"), this.baseURI).toString();
    }

    connectedCallback(){
        this.load()
    }

    async load(){
        let res = await fetch(this.src);
        if(!res.ok){
            console.error(`Server responded with code ${res.status} ${res.statusText}`)
            return
        }

        let htmlStr = await res.text()
        let html = new DOMParser().parseFromString(htmlStr, "text/html");

        this.content.replaceChildren(...Array.from(html.querySelector("body").childNodes))
    }
}

customElements.define("camp-html", HTMLImportElement, {extends: "template"})