fix(debugger): copy structured variable values with their contents (#1904) (#1917)

src/features/debugger/valueText.ts

@@ -0,0 +1,53 @@
+/** Text for "Copy Value": a structured value (array, object, map) is copied with its contents, not its summary. */
+import type { Variable } from "@/platform/ipc";
+
+export interface ValueTextRoot {
+  value: string;
+  reference: number;
+}
+
+export interface ValueTextLimits {
+  depth: number;
+  entries: number;
+}
+
+export const VALUE_TEXT_LIMITS: ValueTextLimits = { depth: 8, entries: 2000 };
+
+/**
+ * `value` alone for a scalar; for an expandable value the summary line followed by its children,
+ * one per line and indented by depth. Cycles and anything past the limits end in an ellipsis line.
+ */
+export async function valueText(
+  root: ValueTextRoot,
+  fetchChildren: (reference: number) => Promise<Variable[]>,
+  limits: ValueTextLimits = VALUE_TEXT_LIMITS,
+): Promise<string> {
+  if (root.reference <= 0) return root.value;
+  const lines = [root.value];
+  let budget = limits.entries;
+  const path = new Set<number>([root.reference]);
+
+  const walk = async (reference: number, depth: number): Promise<void> => {
+    const pad = "  ".repeat(depth);
+    if (depth > limits.depth) {
+      lines.push(`${pad}…`);
+      return;
+    }
+    for (const child of await fetchChildren(reference)) {
+      if (budget-- <= 0) {
+        lines.push(`${pad}…`);
+        return;
+      }
+      lines.push(`${pad}${child.name}: ${child.value}`);
+      const ref = child.variablesReference;
+      if (ref > 0 && !path.has(ref)) {
+        path.add(ref);
+        await walk(ref, depth + 1);
+        path.delete(ref);
+      }
+    }
+  };
+
+  await walk(root.reference, 1);
+  return lines.join("\n");
+}