1 files changed, 118 insertions, 0 deletions
diff --git a/packages/webapi/src/lib/Element.ts b/packages/webapi/src/lib/Element.ts
new file mode 100644
index 000000000..ec096fb6d
--- /dev/null
+++ b/packages/webapi/src/lib/Element.ts
@@ -0,0 +1,118 @@
+import * as _ from './utils'
+
+export class Element extends Node {
+	hasAttribute(name: string): boolean {
+		void name
+
+		return false
+	}
+
+	getAttribute(name: string): string | null {
+		return null
+	}
+
+	setAttribute(name: string, value: string): void {
+		void name
+		void value
+	}
+
+	removeAttribute(name: string): void {
+		void name
+	}
+
+	attachShadow(init: Partial<ShadowRootInit>) {
+		if (arguments.length < 1) throw new TypeError(`Failed to execute 'attachShadow' on 'Element': 1 argument required, but only 0 present.`)
+
+		if (init !== Object(init)) throw new TypeError(`Failed to execute 'attachShadow' on 'Element': The provided value is not of type 'ShadowRootInit'.`)
+
+		if (init.mode !== 'open' && init.mode !== 'closed') throw new TypeError(`Failed to execute 'attachShadow' on 'Element': Failed to read the 'mode' property from 'ShadowRootInit': The provided value '${init.mode}' is not a valid enum value of type ShadowRootMode.`)
+
+		const internals = _.internalsOf<ElementInternals>(this, 'Element', 'attachShadow')
+
+		if (internals.shadowRoot) throw new Error('The operation is not supported.')
+
+		internals.shadowInit = internals.shadowInit || {
+			mode: init.mode,
+			delegatesFocus: Boolean(init.delegatesFocus),
+		}
+
+		internals.shadowRoot = internals.shadowRoot || (/^open$/.test(internals.shadowInit.mode as string) ? Object.setPrototypeOf(new EventTarget(), ShadowRoot.prototype) as ShadowRoot : null)
+
+		return internals.shadowRoot
+	}
+
+	get assignedSlot(): HTMLSlotElement | null {
+		return null
+	}
+
+	get innerHTML(): string {
+		_.internalsOf<ElementInternals>(this, 'Element', 'innerHTML')
+
+		return ''
+	}
+
+	set innerHTML(value) {
+		_.internalsOf<ElementInternals>(this, 'Element', 'innerHTML')
+
+		void value
+	}
+
+	get shadowRoot(): ShadowRoot | null {
+		const internals = _.internalsOf<ElementInternals>(this, 'Element', 'shadowRoot')
+
+		return Object(internals.shadowInit).mode === 'open' ? internals.shadowRoot : null
+	}
+
+	get localName(): string {
+		return _.internalsOf<ElementInternals>(this, 'Element', 'localName').localName as string
+	}
+
+	get nodeName(): string {
+		return (_.internalsOf<ElementInternals>(this, 'Element', 'nodeName').localName as string).toUpperCase()
+	}
+
+	get tagName(): string {
+		return (_.internalsOf<ElementInternals>(this, 'Element', 'tagName').localName as string).toUpperCase()
+	}
+}
+
+export class HTMLElement extends Element {}
+
+export class HTMLBodyElement extends HTMLElement {}
+
+export class HTMLDivElement extends HTMLElement {}
+
+export class HTMLHeadElement extends HTMLElement {}
+
+export class HTMLHtmlElement extends HTMLElement {}
+
+export class HTMLSpanElement extends HTMLElement {}
+
+export class HTMLStyleElement extends HTMLElement {}
+
+export class HTMLTemplateElement extends HTMLElement {}
+
+export class HTMLUnknownElement extends HTMLElement {}
+
+_.allowStringTag(Element)
+_.allowStringTag(HTMLElement)
+_.allowStringTag(HTMLBodyElement)
+_.allowStringTag(HTMLDivElement)
+_.allowStringTag(HTMLHeadElement)
+_.allowStringTag(HTMLHtmlElement)
+_.allowStringTag(HTMLSpanElement)
+_.allowStringTag(HTMLStyleElement)
+_.allowStringTag(HTMLTemplateElement)
+_.allowStringTag(HTMLUnknownElement)
+
+export interface ElementInternals {
+	attributes: { [name: string]: string },
+	localName?: string
+	shadowRoot: ShadowRoot | null
+	shadowInit: ShadowRootInit | void
+}
+
+export interface ShadowRootInit {
+	mode: 'open' | 'closed'
+	delegatesFocus: boolean
+}
+\ No newline at end of file