Tree lens: collapse path-shaped query results into a forest

packages/core/src/catalog/index.test.ts

@@ -1,6 +1,7 @@
 import { describe, it, expect } from "vitest";
 import {
   assembleLensSpec,
+  buildForest,
   lensComponents,
   type QueryResult,
 } from "./index.js";
@@ -17,7 +18,7 @@ const fakeResult: QueryResult = {
 };
 
 describe("lensComponents", () => {
-  it("registers all fourteen components (9 lenses + 5 controls)", () => {
+  it("registers all fifteen components (10 lenses + 5 controls)", () => {
     expect(Object.keys(lensComponents).sort()).toEqual([
       "ActionList",
       "Button",
@@ -33,6 +34,7 @@ describe("lensComponents", () => {
       "TextInput",
       "Timeline",
       "Toggle",
+      "Tree",
     ]);
   });
 
@@ -294,3 +296,79 @@ describe("Form picker field schema", () => {
     ).toThrow(/require kind: picker/);
   });
 });
+
+describe("Tree lens", () => {
+  it("builds a Tree spec with rows merged in", () => {
+    const spec = assembleLensSpec(
+      "t1",
+      "Tree",
+      {
+        levels: [
+          { key: "d.slug", label: "d.name" },
+          { key: "c.slug", label: "c.name" },
+        ],
+        select_state: "/selected",
+      },
+      fakeResult,
+    );
+    expect(spec.elements["t1"]?.type).toBe("Tree");
+    expect((spec.elements["t1"]?.props as { rows: unknown[] }).rows).toEqual(
+      fakeResult.rows,
+    );
+  });
+
+  it("rejects fewer than two levels", () => {
+    expect(() =>
+      assembleLensSpec("t1", "Tree", { levels: [{ key: "d.slug" }] }, fakeResult),
+    ).toThrow();
+  });
+});
+
+describe("buildForest", () => {
+  const LEVELS = [
+    { key: "d", label: "dn" },
+    { key: "c", label: "cn" },
+    { key: "r", label: "rn" },
+  ];
+
+  it("groups shared prefixes, dedupes, keeps first-seen order and labels", () => {
+    const rows = [
+      { d: "sys", dn: "Systems", c: "loop", cn: "Feedback loops", r: "attr", rn: "Attractors" },
+      { d: "sys", dn: "Systems", c: "loop", cn: "Feedback loops", r: "emer", rn: "Emergence" },
+      { d: "sys", dn: "Systems", c: "chunk", cn: "Chunking", r: "attr", rn: "Attractors" },
+      { d: "cog", dn: "Cognitive", c: "bias", cn: "Bias", r: "loop", rn: "Feedback loops" },
+      // duplicate full path — must not duplicate nodes
+      { d: "sys", dn: "Systems", c: "loop", cn: "Feedback loops", r: "attr", rn: "Attractors" },
+    ];
+    const forest = buildForest(rows, LEVELS);
+    expect(forest.map((n) => n.label)).toEqual(["Systems", "Cognitive"]);
+    const sys = forest[0]!;
+    expect(sys.children.map((n) => n.label)).toEqual(["Feedback loops", "Chunking"]);
+    expect(sys.children[0]!.children.map((n) => n.label)).toEqual([
+      "Attractors",
+      "Emergence",
+    ]);
+    // same key under different parents = distinct nodes with distinct paths
+    const cogLoop = forest[1]!.children[0]!.children[0]!;
+    expect(cogLoop.key).toBe("loop");
+    expect(cogLoop.path).not.toBe(sys.children[0]!.path);
+    expect(cogLoop.depth).toBe(2);
+  });
+
+  it("truncates sparse paths at the first empty level and falls back to key as label", () => {
+    const rows = [
+      { d: "sys", dn: "Systems", c: "solo", cn: null, r: null, rn: null },
+      { d: "sys", dn: "Systems", c: "", cn: "ignored" },
+      { d: "lonely" }, // level-1-only row, no label column value
+    ];
+    const forest = buildForest(rows, LEVELS);
+    expect(forest.map((n) => n.label)).toEqual(["Systems", "lonely"]);
+    const solo = forest[0]!.children[0]!;
+    expect(solo.label).toBe("solo"); // null label → key fallback
+    expect(solo.children).toEqual([]);
+  });
+
+  it("returns an empty forest for no rows", () => {
+    expect(buildForest([], LEVELS)).toEqual([]);
+  });
+});

packages/core/src/catalog/index.ts

@@ -8,6 +8,13 @@ import {
   type TableAuthorProps,
   type TableRuntimeProps,
 } from "./lenses/table.js";
+import {
+  TreeAuthorPropsSchema,
+  TreeRuntimePropsSchema,
+  TreeDescription,
+  type TreeAuthorProps,
+  type TreeRuntimeProps,
+} from "./lenses/tree.js";
 import {
   PathAuthorPropsSchema,
   PathRuntimePropsSchema,
@@ -88,6 +95,7 @@ import {
 } from "./lenses/number_input.js";
 
 export * from "./lenses/table.js";
+export * from "./lenses/tree.js";
 export * from "./lenses/path.js";
 export * from "./lenses/subgraph.js";
 export * from "./lenses/action_list.js";
@@ -129,6 +137,7 @@ export interface QueryResult {
  */
 export const lensComponents = {
   Table:      { props: TableRuntimePropsSchema,      description: TableDescription },
+  Tree:       { props: TreeRuntimePropsSchema,       description: TreeDescription },
   Path:       { props: PathRuntimePropsSchema,       description: PathDescription },
   Subgraph:   { props: SubgraphRuntimePropsSchema,   description: SubgraphDescription },
   ActionList: { props: ActionListRuntimePropsSchema, description: ActionListDescription },
@@ -263,6 +272,11 @@ function buildRuntimeProps(
       const runtime: TableRuntimeProps = { ...author, rows: result.rows };
       return runtime as unknown as Record<string, unknown>;
     }
+    case "Tree": {
+      const author: TreeAuthorProps = TreeAuthorPropsSchema.parse(authorProps);
+      const runtime: TreeRuntimeProps = { ...author, rows: result.rows };
+      return runtime as unknown as Record<string, unknown>;
+    }
     case "Path": {
       const author: PathAuthorProps = PathAuthorPropsSchema.parse(authorProps);
       const runtime: PathRuntimeProps = { ...author, rows: result.rows };

packages/core/src/spec/index.ts

@@ -4,6 +4,7 @@ import { parse as parseYaml } from "yaml";
 /** Data-bearing lenses (cells with a query; Form's query is optional — prefill). */
 export const LensKind = z.enum([
   "Table",
+  "Tree",
   "Subgraph",
   "Path",
   "ActionList",
@@ -28,6 +29,7 @@ export type ControlKind = z.infer<typeof ControlKind>;
 /** Any cell type. */
 export const ComponentKind = z.enum([
   "Table",
+  "Tree",
   "Subgraph",
   "Path",
   "ActionList",

packages/tui/src/components/Tree.tsx

@@ -0,0 +1,148 @@
+import React, { useMemo, useState } from "react";
+import { Box, Text, useFocus, useInput } from "ink";
+import { useActions, useStateValue } from "@json-render/ink";
+import {
+  buildForest,
+  type TreeNode,
+  type TreeRuntimeProps,
+} from "@modernrelay/notebook-core";
+
+interface ComponentCtx<P> {
+  props: P;
+}
+
+const VISIBLE_LINES = 14;
+
+interface VisibleLine {
+  node: TreeNode;
+  prefix: string;
+}
+
+/** Flatten the expanded forest into display lines with box-drawing prefixes. */
+function visibleLines(
+  nodes: TreeNode[],
+  expanded: ReadonlySet<string>,
+  ancestors = "",
+): VisibleLine[] {
+  const out: VisibleLine[] = [];
+  nodes.forEach((node, index) => {
+    const last = index === nodes.length - 1;
+    const branch = node.depth === 0 ? "" : last ? "└─ " : "├─ ";
+    out.push({ node, prefix: ancestors + branch });
+    if (node.children.length > 0 && expanded.has(node.path)) {
+      const carry = node.depth === 0 ? "" : last ? "   " : "│  ";
+      out.push(...visibleLines(node.children, expanded, ancestors + carry));
+    }
+  });
+  return out;
+}
+
+/**
+ * Tree lens (ink) — the expanded forest as box-drawing lines. ↑/↓ move the
+ * cursor, ←/→ collapse/expand the focused node, Enter/space writes the
+ * node's key value to `select_state` (same dispatch as Table).
+ */
+export function Tree({
+  props: p,
+}: ComponentCtx<TreeRuntimeProps>): React.ReactElement {
+  const actions = useActions();
+  const selectable = Boolean(p.select_state);
+  const { isFocused } = useFocus({ autoFocus: selectable });
+  const selected = useStateValue<string>(p.select_state ?? "/__never__");
+  const forest = useMemo(() => buildForest(p.rows, p.levels), [p.rows, p.levels]);
+  const [expanded, setExpanded] = useState<Set<string>>(() => {
+    const open = new Set<string>();
+    const walk = (nodes: TreeNode[]): void => {
+      for (const node of nodes) {
+        if (
+          node.children.length > 0 &&
+          (p.expand_depth === undefined || node.depth < p.expand_depth)
+        ) {
+          open.add(node.path);
+        }
+        walk(node.children);
+      }
+    };
+    walk(forest);
+    return open;
+  });
+  const [cursor, setCursor] = useState(0);
+
+  const lines = visibleLines(forest, expanded);
+  const total = lines.length;
+
+  useInput(
+    (input, key) => {
+      if (total === 0) return;
+      const line = lines[Math.min(cursor, total - 1)];
+      if (key.upArrow) setCursor((c) => (c - 1 + total) % total);
+      else if (key.downArrow) setCursor((c) => (c + 1) % total);
+      else if (key.leftArrow && line) {
+        setExpanded((prev) => {
+          const next = new Set(prev);
+          next.delete(line.node.path);
+          return next;
+        });
+      } else if (key.rightArrow && line && line.node.children.length > 0) {
+        setExpanded((prev) => new Set(prev).add(line.node.path));
+      } else if ((key.return || input === " ") && line && selectable) {
+        actions.execute({
+          action: "setState",
+          params: { statePath: p.select_state, value: line.node.key },
+        });
+      }
+    },
+    { isActive: isFocused },
+  );
+
+  if (total === 0) {
+    return <Text dimColor>{p.empty_text ?? "(no rows)"}</Text>;
+  }
+
+  const cur = Math.min(cursor, total - 1);
+  const start = Math.max(
+    0,
+    Math.min(cur - Math.floor(VISIBLE_LINES / 2), total - VISIBLE_LINES),
+  );
+  const window = lines.slice(start, start + VISIBLE_LINES);
+  const showCounts = p.counts !== false;
+
+  return (
+    <Box flexDirection="column">
+      {p.title && <Text bold>{p.title}</Text>}
+      {window.map((line, i) => {
+        const index = start + i;
+        const isCursor = isFocused && index === cur;
+        const isSelected = selectable && line.node.key === selected;
+        const hasChildren = line.node.children.length > 0;
+        const disclosure = hasChildren
+          ? expanded.has(line.node.path)
+            ? "▾ "
+            : "▸ "
+          : "";
+        return (
+          <Box key={line.node.path}>
+            <Text color={isCursor ? "cyan" : isSelected ? "green" : undefined}>
+              {isCursor ? "▶ " : isSelected ? "● " : "  "}
+              <Text dimColor>{line.prefix}</Text>
+              {disclosure}
+              <Text bold={line.node.depth === 0}>{line.node.label}</Text>
+              {showCounts && hasChildren && (
+                <Text dimColor> ({line.node.children.length})</Text>
+              )}
+            </Text>
+          </Box>
+        );
+      })}
+      {total > VISIBLE_LINES && (
+        <Text dimColor>
+          {" "}
+          {cur + 1}/{total}
+        </Text>
+      )}
+      {isFocused && (
+        <Text dimColor> ↑/↓ move · ←/→ fold{selectable ? " · Enter select" : ""}</Text>
+      )}
+    </Box>
+  );
+}

packages/tui/src/registry.ts

@@ -2,6 +2,7 @@ import { defineCatalog } from "@json-render/core";
 import { schema, defineRegistry } from "@json-render/ink";
 import { lensActions, lensComponents } from "@modernrelay/notebook-core";
 import { Table } from "./components/Table.js";
+import { Tree } from "./components/Tree.js";
 import { Path } from "./components/Path.js";
 import { Subgraph } from "./components/Subgraph.js";
 import { ActionList } from "./components/ActionList.js";
@@ -22,7 +23,8 @@ const catalog = defineCatalog(schema, {
 });
 
 const { registry: inkRegistry } = defineRegistry(catalog, {
-  components: { Table, Path, Subgraph, ActionList, Form, Timeline, Card, Quote, Text, Button, Toggle, Select, TextInput, NumberInput },
+  components: { Table,
+    Tree, Path, Subgraph, ActionList, Form, Timeline, Card, Quote, Text, Button, Toggle, Select, TextInput, NumberInput },
   actions: {
     setState: async (params, setState) => {
       const { statePath, value } = params as { statePath: string; value: unknown };