feat(editor-toolbar): create DictyLinkNode to extend LinkNode and add…

… filename as download attribute

This change introduces a new node type, `DictyLinkNode`, which extends the existing `LinkNode` from `@lexical/link`. This new node allows specifying a `download` attribute, effectively setting a suggested filename when the linked resource is downloaded. The filename is extracted from the attributes during node construction, leveraging `fp-ts` for safe handling of nullable or undefined values. This enhancement provides more control over how links are handled, particularly for downloadable resources.

packages/editor-toolbar/DictyLinkNode.ts

@@ -0,0 +1,29 @@
+import { NodeKey } from "lexical"
+import { LinkNode, LinkAttributes } from "@lexical/link"
+import { pipe } from "fp-ts/function"
+import {
+  fromNullable as OfromNullable,
+  flatMap as OflatMap,
+  match as Omatch,
+} from "fp-ts/Option"
+
+type DictyLinkAttributes = LinkAttributes & {
+  download?: null | string
+}
+
+class DictyLinkNode extends LinkNode {
+  __download: string
+
+  constructor(url: string, attributes?: DictyLinkAttributes, key?: NodeKey) {
+    super(url, attributes, key)
+    const filename = pipe(
+      attributes,
+      OfromNullable,
+      OflatMap(({ download }) => OfromNullable(download)),
+      Omatch(() =>  "", (f) => f)
+    )
+    this.__download = filename
+  }
+}
+
+export { DictyLinkNode }