finish embed components

library/embed/embed-footer.tsx

@@ -0,0 +1,32 @@
+import React from "react"
+import { ReacordElement } from "../element.js"
+import { EmbedChildNode } from "./embed-child.js"
+import type { EmbedOptions } from "./embed-options"
+
+export type EmbedFooterProps = {
+  text?: string
+  children?: string
+  iconUrl?: string
+  timestamp?: string | number | Date
+}
+
+export function EmbedFooter(props: EmbedFooterProps) {
+  return (
+    <ReacordElement
+      props={props}
+      createNode={() => new EmbedFooterNode(props)}
+    />
+  )
+}
+
+class EmbedFooterNode extends EmbedChildNode<EmbedFooterProps> {
+  override modifyEmbedOptions(options: EmbedOptions): void {
+    options.footer = {
+      text: this.props.text ?? this.props.children ?? "",
+      icon_url: this.props.iconUrl,
+    }
+    options.timestamp = this.props.timestamp
+      ? new Date(this.props.timestamp).toISOString()
+      : undefined
+  }
+}