Lexical: Improved table row copy/paste

Added safeguarding/matching of source/target sizes to prevent broken
tables.

resources/js/wysiwyg/utils/node-clipboard.ts

@@ -0,0 +1,56 @@
+import {$isElementNode, LexicalEditor, LexicalNode, SerializedLexicalNode} from "lexical";
+
+type SerializedLexicalNodeWithChildren = {
+    node: SerializedLexicalNode,
+    children: SerializedLexicalNodeWithChildren[],
+};
+
+function serializeNodeRecursive(node: LexicalNode): SerializedLexicalNodeWithChildren {
+    const childNodes = $isElementNode(node) ? node.getChildren() : [];
+    return {
+        node: node.exportJSON(),
+        children: childNodes.map(n => serializeNodeRecursive(n)),
+    };
+}
+
+function unserializeNodeRecursive(editor: LexicalEditor, {node, children}: SerializedLexicalNodeWithChildren): LexicalNode|null {
+    const instance = editor._nodes.get(node.type)?.klass.importJSON(node);
+    if (!instance) {
+        return null;
+    }
+
+    const childNodes = children.map(child => unserializeNodeRecursive(editor, child));
+    for (const child of childNodes) {
+        if (child && $isElementNode(instance)) {
+            instance.append(child);
+        }
+    }
+
+    return instance;
+}
+
+export class NodeClipboard<T extends LexicalNode> {
+    nodeClass: {importJSON: (s: SerializedLexicalNode) => T};
+    protected store: SerializedLexicalNodeWithChildren[] = [];
+
+    constructor(nodeClass: {importJSON: (s: any) => T}) {
+        this.nodeClass = nodeClass;
+    }
+
+    set(...nodes: LexicalNode[]): void {
+        this.store.splice(0, this.store.length);
+        for (const node of nodes) {
+            this.store.push(serializeNodeRecursive(node));
+        }
+    }
+
+    get(editor: LexicalEditor): T[] {
+        return this.store.map(json => unserializeNodeRecursive(editor, json)).filter((node) => {
+            return node !== null;
+        }) as T[];
+    }
+
+    size(): number {
+        return this.store.length;
+    }
+}