Editor: view-scoped Extract-to-Dataset for inline and self-defined data

docs/architecture/03-modal-system.md

@@ -75,7 +75,10 @@ export interface ModalConfig {
   component: ComponentType<any>; // the body rendered inside the shell
 
   /** Initialize transient modal state when it opens. `arg` carries an
-   *  optional sub-target (e.g. a dataset id for chartBuilder/extract). */
+   *  optional sub-target (e.g. a dataset id for chartBuilder/datasets). OMIT
+   *  when a service seeds the store *before* `openModal` — Extract is seeded by
+   *  `services/extract-action` from the editor cursor, and an `init` here would
+   *  re-read and clobber that view-scoped capture. */
   init?: (arg?: string) => void;
 
   /** Serializable snapshot of in-progress edits, used to detect unsaved

docs/architecture/07-naming-and-relationships.md

@@ -164,35 +164,18 @@ export function libraryRefName(data: unknown, selfDefined: ReadonlySet<string>):
 
 References appear in several places — top-level `data`, per-layer `data`, `data`
 inside `spec`/`facet`/`hconcat`/`vconcat`, and a lookup transform's `from.data`.
-Rather than enumerate the grammar, each pass walks the spec recursively but
-**prunes two keys**: a `data` object's payload (its `values`/rows) and the
-top-level `datasets` map hold user data, not nested specs. Without the prune, a
-data _row_ carrying a field literally named `data: { name: "x" }` is misread as a
-reference.
+Rather than enumerate the grammar, the walk recurses the spec but **prunes two
+keys**: a `data` object's payload (its `values`/rows) and the top-level `datasets`
+map hold user data, not nested specs. Without the prune, a data _row_ carrying a
+field literally named `data: { name: "x" }` is misread as a reference.
 
-```ts
-// src/core/spec-refs.ts — the recursive walk; classification routes through spec-data
-
-export function extractDatasetRefs(spec: Json): string[] {
-  const root = typeof spec === 'string' ? safeParse(spec) : spec; // unparseable → no refs
-  const selfDefined = selfDefinedNames(root);
-  const names = new Set<string>();
-  const walk = (node: Json): void => {
-    if (Array.isArray(node)) return void node.forEach(walk);
-    if (node && typeof node === 'object') {
-      const obj = node as Record<string, Json>;
-      const refName = libraryRefName(obj.data, selfDefined);
-      if (refName !== null) names.add(refName);
-      for (const key of Object.keys(obj)) {
-        if (key === 'data' || key === 'datasets') continue; // prune user-data payloads
-        walk(obj[key]);
-      }
-    }
-  };
-  walk(root);
-  return [...names];
-}
-```
+That walk is **one shared pair** in `core/spec-data`, not re-implemented per pass:
+`forEachDataBinding(spec, visit)` (read-only, `visit` returns `true` to stop early)
+and `mapDataBindings(spec, mapData)` (returns a copy). Both compute the spec's
+self-defined names once and hand them to the callback, so a caller writes only its
+own rule — _what is a reference_ (`libraryRefName`) or _what to rewrite_ — never the
+walk. `extractDatasetRefs` collects through `forEachDataBinding`; `renameDatasetInSpec`
+and `promoteSelfDefinedDataset` (§3.2) rewrite through `mapDataBindings`.
 
 `recomputeDatasetRefs` is the thin sorted/de-duped wrapper stored on
 `snippet.datasetRefs`, run on every draft change and on publish.
@@ -211,22 +194,50 @@ export function extractDatasetRefs(spec: Json): string[] {
   programmatic extract/revert rewrites, never on raw keystrokes. That keeps the
   links in step with the edited draft while never recomputing from a
   transiently-invalid spec.
-- Keep the three ref walks in lockstep — extraction here, `renameDatasetInSpec`,
-  and the renderer's `resolveDatasetRefs` (`src/core/rendering.ts`). They agree
-  because they share both halves: the `libraryRefName` classifier (what is a
-  reference) and the prune of the **same two keys** (`data`, `datasets`). If one
-  classified differently, or descended into data payloads while another didn't, a
-  row field named `data` would get counted, rewritten, or throw
-  `DatasetNotFoundError`.
+- Route every binding pass through the shared `forEachDataBinding` /
+  `mapDataBindings`. They share both halves that must agree — the `libraryRefName`
+  classifier (what is a reference) and the prune of the **same two keys** (`data`,
+  `datasets`) — so extraction, rename, and the reverse extraction cannot drift. If
+  one classified differently, or descended into data payloads while another didn't,
+  a row field named `data` would get counted, rewritten, or throw
+  `DatasetNotFoundError`. (The renderer's `resolveDatasetRefs` mutates in place and
+  can throw mid-walk, so it keeps its own copy of the walk — the one exception, held
+  in step by the same prune-two-keys rule.)
 
 **Don't**
 
 - Don't let two code paths each have their own idea of "referenced names".
   Renamer, ref-recomputer, and renderer must use the same walk shape.
+- Don't add a fresh prune-walk for a new binding pass — reuse the shared pair. A
+  hand-written copy is one classifier tweak away from disagreeing with the others.
 - Don't "enumerate the grammar" (scope the walk to a fixed list of container
   keys) to fix the payload-descent problem — pruning the two data-bearing keys
   stays correct as Vega-Lite's composition grammar grows; an allow-list rots.
 
+### 3.2 Extracting embedded data into a dataset — the reverse (`spec-inline-data.ts`, `spec-refs.ts`)
+
+Extract-to-Dataset is the inverse of a reference: it lifts a view's **embedded**
+data into a stored dataset and rewrites the spec to reference it by name. It is a
+cursor-scoped editor action — `services/extract-action` resolves the focused view's
+binding (`dataBindingAtPath`), seeds the modal, then opens it; the gate
+`specHasExtractableData` hides the toolbar action when no view carries liftable
+data. Two embedded shapes lift, both routing through the same `spec-data` classifier
+so they never disagree with reference detection:
+
+- **Inline `values`** — `inlineValuesOf` captures the payload verbatim (a CSV/TSV
+  string is kept as-is); confirm rewrites that view's `data` block, at its anchor
+  path, to `{ name }`.
+- **A self-defined `datasets` entry** the view references — `selfDefinedPayloadOf`
+  reads the named rows and `promoteSelfDefinedDataset` drops the `datasets` entry
+  (and the map when it empties). Keeping the name needs no reference rewrite — it
+  un-shadows onto the new library dataset; renaming rewrites every matching
+  reference. This is the reverse direction of the self-defined-vs-library
+  precedence in §3.1.
+
+A `lookup` transform's inline `from.data` lifts like any view binding —
+`dataBindingAtPath` finds it. A `url`, a generator, or an existing library
+reference carries nothing to lift.
+
 ---
 
 ## 4. Reverse lookup: who uses this dataset?

docs/ux-second-pass.md

@@ -8,6 +8,13 @@ record the resolution into the contract (`docs/architecture/09`+`10` and the rel
 
 ## Open
 
+- **Extract-to-Dataset has no keyboard accelerator** — its sibling editor actions (wrap /
+  config, in `spec-transform-actions` / `spec-config-actions`) register an F1-palette command
+  and a lightbulb; Extract is toolbar-only (`runExtract` in `services/extract-action.ts`),
+  because it opens a modal rather than making an in-place undoable edit, so the palette/lightbulb
+  fit awkwardly. Decide whether to add a palette command anyway for parity (a keyboard path to
+  open the modal at the cursor), or leave toolbar-only.
+
 - **Storage-full copy implies a per-tier budget, but quota is whole-origin** — the messages
   say "snippet storage is full" / "dataset storage is full" and tell the user to delete that
   entity's items, yet IndexedDB quota is shared across the whole origin. Per-tier framing is

src/app/components/ExtractModal.tsx

@@ -1,7 +1,7 @@
 /**
  * Extract-to-Dataset — the modal body (spec §03F).
  *
- * Shows a read-only preview of the active snippet draft's inline data and asks
+ * Shows a read-only preview of the focused view's embedded data and asks
  * for a dataset name. On confirm it saves the data as a new dataset and rewrites
  * the draft to reference it by name (logic in ExtractStore), then force-closes
  * (the commit is the user's confirmation, so no discard prompt). Cancel leaves
@@ -38,13 +38,13 @@ export function ExtractModal() {
   };
 
   if (!source) {
-    return <p className={styles.muted}>This snippet has no inline data to extract.</p>;
+    return <p className={styles.muted}>This snippet has no embedded data to extract.</p>;
   }
 
   return (
     <div className={styles.extract}>
       <p className={styles.intro}>
-        Save this snippet&rsquo;s inline data as a reusable dataset. The spec will be rewritten to
+        Save this snippet&rsquo;s embedded data as a reusable dataset. The spec will be rewritten to
         reference it by name.
       </p>
 

src/app/components/SpecEditor.tsx

@@ -26,7 +26,7 @@ import '../infrastructure/monaco-env'; // side-effect: wire workers before creat
 import { configureVegaLiteJson } from '../infrastructure/monaco-schema';
 import { configureJsonFormatter, installFormatOnPaste } from '../infrastructure/monaco-format';
 import { parseChartSpecText } from '@core/chart-builder';
-import { openChartBuilderForEdit, openModal } from '../modals/ModalCoordinator';
+import { openChartBuilderForEdit } from '../modals/ModalCoordinator';
 import {
   installSpecConfigActions,
   runExtractConfig,
@@ -41,10 +41,11 @@ import {
   runWrap,
 } from '../services/spec-transform-actions';
 import { configureSpecDatasetHints } from '../services/spec-dataset-hints';
+import { runExtract } from '../services/extract-action';
 import { useAppStore } from '../stores/AppStore';
 import { confirm } from '../stores/ConfirmStore';
 import { useDatasetStore } from '../stores/DatasetStore';
-import { hasInlineData } from '../stores/ExtractStore';
+import { hasExtractableData } from '../stores/ExtractStore';
 import { publishActiveSnippet } from '../services/snippet-actions';
 import { notify } from '../stores/NotificationStore';
 import { usePreviewStore } from '../stores/PreviewStore';
@@ -222,10 +223,11 @@ function EditorToolbar({
     const draft = s.editorView === 'draft' ? s.draftText : active.draftSpec;
     return draft !== active.spec;
   });
-  // Offer Extract only when the live draft carries top-level inline data to lift
-  // out (spec §03F → hidden when the spec has no inline data).
+  // Offer Extract only when the live draft carries data to lift out — inline
+  // `values` in any view, or a reference to a self-defined `datasets` entry (spec
+  // §03F → hidden when there is nothing extractable).
   const canExtract = useSnippetStore(
-    (s) => s.activeSnippetId !== null && hasInlineData(s.draftText),
+    (s) => s.activeSnippetId !== null && hasExtractableData(s.draftText),
   );
 
   // Offer "Open in builder" only when the active snippet's published spec is
@@ -248,6 +250,14 @@ function EditorToolbar({
     if (snippet) openChartBuilderForEdit(snippet);
   };
 
+  // Extract is scoped to the view at the cursor (services/extract-action), so it
+  // goes through the editor handle like the wrap/config actions, not a bare
+  // openModal — the service captures the focused binding before opening the modal.
+  const handleExtract = () => {
+    const editor = editorRef.current;
+    if (editor) runExtract(editor);
+  };
+
   // Publish + its success toast live in one place (services/snippet-actions) so
   // the button and the Cmd/Ctrl+S shortcut (EventRouter) behave identically.
   const handlePublish = publishActiveSnippet;
@@ -315,8 +325,8 @@ function EditorToolbar({
       {canExtract && (
         <Button
           className={styles.collapsible}
-          onClick={() => openModal('extract')}
-          title="Extract inline data into a reusable dataset"
+          onClick={handleExtract}
+          title="Extract embedded data into a reusable dataset"
           aria-label="Extract to Dataset"
         >
           <Icon name="dataset" className={styles.actionIcon} />

src/app/modals/modal-registry.ts

@@ -63,11 +63,12 @@ const MODAL_REGISTRY: Partial<Record<ModalName, ModalConfig>> = {
     },
   },
 
-  // Opened from the snippet editor with the active draft's inline data to lift out.
+  // Opened from the snippet editor by `services/extract-action`, which seeds the
+  // store with the focused view's inline data (`begin`) *before* opening — so no
+  // `init` here, which would re-read top-level and clobber the view-scoped capture.
   extract: {
     name: 'extract',
     title: 'Extract to Dataset',
-    init: () => useExtractStore.getState().init(),
     getState: () => ({ name: useExtractStore.getState().name }),
   },
 

src/app/services/extract-action.ts

@@ -0,0 +1,82 @@
+/**
+ * Extract-to-Dataset as an editor action (spec §03F; docs/architecture/08 →
+ * editor augmentation) — the data-facing counterpart to the wrap/config actions.
+ *
+ * Resolves the embedded data of the **view the cursor sits in** (the nearest
+ * enclosing `data` binding, honoring Vega-Lite's parent→child inheritance), seeds
+ * the Extract modal with it, and opens the modal. The cursor picks which view to
+ * extract; a single-view spec resolves to the root binding from any cursor, so the
+ * common case needs no thought. Two binding shapes are liftable — a view's inline
+ * `data.values`, and a `{ name }` reference to the spec's own top-level `datasets`
+ * (the data lives in the `datasets` map; we pre-fill the modal with its name).
+ *
+ * The toolbar offers the action whenever *some* view has extractable data
+ * (`hasExtractableData`); when the focused view itself has none — it references a
+ * library dataset, a url, a generator — there is nothing to lift here, so guide the
+ * user to a view that does rather than silently extract the wrong one.
+ */
+
+import type * as monaco from 'monaco-editor/esm/vs/editor/edcore.main';
+import { pathAtOffset } from '@core/spec-cursor';
+import { dataBindingAtPath } from '@core/spec-data';
+import { inlineValuesOf, selfDefinedPayloadOf } from '@core/spec-inline-data';
+import { openModal } from '../modals/ModalCoordinator';
+import { type ExtractTarget, useExtractStore } from '../stores/ExtractStore';
+import { notify } from '../stores/NotificationStore';
+
+// TODO(ux-second-pass): toolbar-only — no F1-palette accelerator like the sibling
+// wrap/config actions, since this opens a modal rather than an in-place edit.
+/** Open Extract-to-Dataset scoped to the view at the cursor. */
+export function runExtract(editor: monaco.editor.IStandaloneCodeEditor): void {
+  const model = editor.getModel();
+  if (!model) return;
+  const text = model.getValue();
+
+  let spec: unknown;
+  try {
+    spec = JSON.parse(text);
+  } catch {
+    notify({
+      kind: 'info',
+      title: 'Can’t extract yet',
+      message: 'Fix the JSON so the spec parses, then extract.',
+    });
+    return;
+  }
+
+  const position = editor.getPosition();
+  const offset = position ? model.getOffsetAt(position) : 0;
+  const binding = dataBindingAtPath(spec, pathAtOffset(text, offset));
+
+  // Inline `values` → rewrite this view's data block; a self-defined `datasets`
+  // reference → lift the named entry and pre-fill the modal with that name.
+  const inline = binding && inlineValuesOf(binding.data);
+  const selfDefined = binding && !inline && selfDefinedPayloadOf(spec, binding.data);
+  let seed: {
+    source: ReturnType<typeof inlineValuesOf>;
+    target: ExtractTarget;
+    name?: string;
+  } | null = null;
+  if (binding && inline) {
+    seed = { source: inline, target: { kind: 'inline', anchorPath: binding.anchorPath } };
+  } else if (binding && selfDefined) {
+    const datasetName = (binding.data as { name: string }).name;
+    seed = {
+      source: selfDefined,
+      target: { kind: 'self-defined', datasetName },
+      name: datasetName,
+    };
+  }
+
+  if (!seed || !seed.source) {
+    notify({
+      kind: 'info',
+      title: 'No data to extract here',
+      message: 'Place the cursor in a view with inline or embedded data to extract it.',
+    });
+    return;
+  }
+
+  useExtractStore.getState().begin({ source: seed.source, target: seed.target, name: seed.name });
+  openModal('extract');
+}

src/app/stores/ExtractStore.test.ts

@@ -0,0 +1,199 @@
+import { beforeEach, describe, expect, test } from 'vitest';
+import { createSnippet } from '@core/snippet';
+import { useDatasetStore } from './DatasetStore';
+import { hasExtractableData, useExtractStore } from './ExtractStore';
+import { useSnippetStore } from './SnippetStore';
+
+const extract = () => useExtractStore.getState();
+const snippets = () => useSnippetStore.getState();
+const datasets = () => useDatasetStore.getState();
+
+/** Load a single active snippet whose live draft buffer is `draft`. */
+function activeDraft(draft: string): void {
+  const s = createSnippet({ id: 's', spec: draft, now: new Date('2026-01-01T00:00:00Z') });
+  useSnippetStore.getState().hydrate([s], 's');
+  useSnippetStore.getState().updateDraft(draft);
+}
+
+beforeEach(() => {
+  useExtractStore.getState().reset();
+  useSnippetStore.getState().reset();
+  useDatasetStore.getState().reset();
+});
+
+describe('hasExtractableData', () => {
+  test('true for inline data, false for a library reference or bad JSON', () => {
+    expect(hasExtractableData('{"data":{"values":[{"a":1}]},"mark":"bar"}')).toBe(true);
+    expect(hasExtractableData('{"data":{"name":"sales"}}')).toBe(false);
+    expect(hasExtractableData('not json')).toBe(false);
+  });
+
+  test('true when inline data lives only in a nested view', () => {
+    expect(
+      hasExtractableData('{"layer":[{"data":{"name":"sales"}},{"data":{"values":[{"a":1}]}}]}'),
+    ).toBe(true);
+  });
+
+  test('true for a reference to a self-defined datasets entry', () => {
+    expect(hasExtractableData('{"datasets":{"sales":[{"a":1}]},"data":{"name":"sales"}}')).toBe(
+      true,
+    );
+  });
+});
+
+describe('confirm — inline rewrite', () => {
+  test('extracts the root binding and rewrites it to a by-name reference', () => {
+    activeDraft('{"data":{"values":[{"a":1},{"a":2}]},"mark":"bar"}');
+    extract().begin({
+      source: { values: [{ a: 1 }, { a: 2 }], format: 'json' },
+      target: { kind: 'inline', anchorPath: [] },
+    });
+    extract().setName('Sales');
+
+    expect(extract().confirm(new Date('2026-02-01T00:00:00Z'))).toBe(true);
+
+    const ds = datasets().datasets.find((d) => d.name === 'Sales');
+    expect(ds?.data).toEqual([{ a: 1 }, { a: 2 }]);
+
+    const draft = JSON.parse(snippets().draftText) as { data: unknown; mark: unknown };
+    expect(draft.data).toEqual({ name: 'Sales' });
+    expect(draft.mark).toBe('bar');
+  });
+
+  test('rewrites only the focused view in a composition, leaving siblings intact', () => {
+    activeDraft(
+      JSON.stringify({
+        layer: [{ data: { name: 'sales' }, mark: 'line' }, { data: { values: [{ a: 1 }] } }],
+      }),
+    );
+    extract().begin({
+      source: { values: [{ a: 1 }], format: 'json' },
+      target: { kind: 'inline', anchorPath: ['layer', 1] },
+    });
+    extract().setName('Overlay');
+    expect(extract().confirm()).toBe(true);
+
+    const draft = JSON.parse(snippets().draftText) as { layer: Array<{ data: unknown }> };
+    expect(draft.layer[0].data).toEqual({ name: 'sales' }); // sibling untouched
+    expect(draft.layer[1].data).toEqual({ name: 'Overlay' }); // focused view rewritten
+  });
+
+  test("rewrites a lookup transform's inline from.data (the cursor sits inside it)", () => {
+    activeDraft(
+      JSON.stringify({
+        data: { name: 'Library' },
+        transform: [
+          { lookup: 'k', from: { data: { values: [{ k: 1, v: 9 }] }, key: 'k', fields: ['v'] } },
+        ],
+        mark: 'bar',
+      }),
+    );
+    extract().begin({
+      source: { values: [{ k: 1, v: 9 }], format: 'json' },
+      target: { kind: 'inline', anchorPath: ['transform', 0, 'from'] },
+    });
+    extract().setName('Lookup');
+    expect(extract().confirm()).toBe(true);
+
+    const draft = JSON.parse(snippets().draftText) as {
+      transform: Array<{ from: { data: unknown } }>;
+    };
+    expect(draft.transform[0].from.data).toEqual({ name: 'Lookup' });
+  });
+
+  test('preserves a CSV string payload as a raw-text dataset', () => {
+    activeDraft('{"data":{"values":"a,b\\n1,2","format":{"type":"csv"}},"mark":"bar"}');
+    extract().begin({
+      source: { values: 'a,b\n1,2', format: 'csv' },
+      target: { kind: 'inline', anchorPath: [] },
+    });
+    extract().setName('Raw');
+    expect(extract().confirm()).toBe(true);
+
+    const ds = datasets().datasets.find((d) => d.name === 'Raw');
+    expect(ds?.format).toBe('csv');
+    expect(ds?.data).toBe('a,b\n1,2');
+  });
+});
+
+describe('confirm — self-defined datasets rewrite', () => {
+  test('keeping the name drops the datasets entry; the reference resolves to the library', () => {
+    activeDraft('{"datasets":{"sales":[{"a":1},{"a":2}]},"data":{"name":"sales"},"mark":"bar"}');
+    extract().begin({
+      source: { values: [{ a: 1 }, { a: 2 }], format: 'json' },
+      target: { kind: 'self-defined', datasetName: 'sales' },
+      name: 'sales',
+    });
+    expect(extract().confirm()).toBe(true);
+
+    const ds = datasets().datasets.find((d) => d.name === 'sales');
+    expect(ds?.data).toEqual([{ a: 1 }, { a: 2 }]);
+
+    const draft = JSON.parse(snippets().draftText) as { datasets?: unknown; data: unknown };
+    expect(draft.datasets).toBeUndefined(); // map emptied → removed
+    expect(draft.data).toEqual({ name: 'sales' }); // reference unchanged, now a library ref
+  });
+
+  test('renaming rewrites every reference and keeps other datasets entries', () => {
+    activeDraft(
+      JSON.stringify({
+        datasets: { sales: [{ a: 1 }], other: [{ b: 2 }] },
+        layer: [
+          { data: { name: 'sales' } },
+          { data: { name: 'sales' } },
+          { data: { name: 'other' } },
+        ],
+      }),
+    );
+    extract().begin({
+      source: { values: [{ a: 1 }], format: 'json' },
+      target: { kind: 'self-defined', datasetName: 'sales' },
+      name: 'Sales 2024',
+    });
+    expect(extract().confirm()).toBe(true);
+
+    const draft = JSON.parse(snippets().draftText) as {
+      datasets: Record<string, unknown>;
+      layer: Array<{ data: unknown }>;
+    };
+    expect(draft.layer[0].data).toEqual({ name: 'Sales 2024' }); // both sales refs rewritten
+    expect(draft.layer[1].data).toEqual({ name: 'Sales 2024' });
+    expect(draft.layer[2].data).toEqual({ name: 'other' }); // untouched
+    expect(draft.datasets).toEqual({ other: [{ b: 2 }] }); // sales entry dropped, other kept
+  });
+});
+
+describe('confirm — guards', () => {
+  test('rejects a duplicate name and creates nothing', () => {
+    activeDraft('{"data":{"values":[{"a":1}]}}');
+    extract().begin({
+      source: { values: [{ a: 1 }], format: 'json' },
+      target: { kind: 'inline', anchorPath: [] },
+    });
+    extract().setName('Sales');
+    extract().confirm();
+    const countAfterFirst = datasets().datasets.length;
+
+    activeDraft('{"data":{"values":[{"b":2}]}}');
+    extract().begin({
+      source: { values: [{ b: 2 }], format: 'json' },
+      target: { kind: 'inline', anchorPath: [] },
+    });
+    extract().setName('Sales');
+    expect(extract().confirm()).toBe(false);
+    expect(extract().error).toMatch(/already exists/);
+    expect(datasets().datasets.length).toBe(countAfterFirst);
+  });
+
+  test('refuses when the anchor path no longer resolves, creating nothing', () => {
+    activeDraft('{"data":{"values":[{"a":1}]}}'); // no layer array
+    extract().begin({
+      source: { values: [{ a: 1 }], format: 'json' },
+      target: { kind: 'inline', anchorPath: ['layer', 3] },
+    });
+    extract().setName('Ghost');
+    expect(extract().confirm()).toBe(false);
+    expect(extract().error).toMatch(/Could not locate/);
+    expect(datasets().datasets.length).toBe(0);
+  });
+});

src/app/stores/ExtractStore.ts

@@ -1,92 +1,86 @@
 /**
- * Extract-inline-data → Dataset state (spec §03F).
+ * Extract-embedded-data → Dataset state (spec §03F).
  *
  * Backs the Extract modal: the reverse of a named reference. It captures the
- * active snippet draft's inline data, takes a dataset name, and on confirm saves
- * the data as a new dataset and rewrites the draft so the inline data is replaced
- * by a by-name reference (`{ "data": { "name": … } }`).
+ * embedded data of the **view the cursor sits in**, takes a dataset name, and on
+ * confirm saves the data as a new library dataset and rewrites the spec so the
+ * embedded data is replaced by a by-name reference.
  *
- * Scope (M3): the **top-level** `data` block of the draft spec — the common case
- * for a single-view chart. Inline data nested inside layers/concats is left for a
- * later pass; `hasInlineData` reflects exactly what `confirm` can lift, so the
- * editor only offers the action when this store can act on it.
+ * Two shapes of embedded data, captured as a `target` (spec §03F; multi-view scope
+ * doc M3):
+ *   - **inline** — a view's `data.values`. Confirm rewrites that view's `data`
+ *     block at its anchor path to `{ name }`.
+ *   - **self-defined** — a `{ name: X }` reference to the spec's own top-level
+ *     `datasets.X`. Confirm removes the `datasets` entry (and the map when it
+ *     empties); the reference resolves to the new library dataset, renamed when the
+ *     name changes (`core/spec-refs` → `promoteSelfDefinedDataset`).
+ *
+ * The store is the editor-free side of the flow: it never reads the cursor or the
+ * Monaco model — `services/extract-action` resolves the focused binding and seeds
+ * it via `begin`, so this stays a plain, testable store.
  */
 
 import { create } from 'zustand';
-import type { DataFormat } from '@core/format-detection';
 import { createDataset } from '@core/dataset';
+import { formatSpec } from '@core/json-format';
 import { isNameTaken } from '@core/naming';
+import { setDataBindingAtPath } from '@core/spec-data';
+import { type InlinePayload, specHasExtractableData } from '@core/spec-inline-data';
+import { promoteSelfDefinedDataset } from '@core/spec-refs';
 import { useDatasetStore } from './DatasetStore';
 import { notify } from './NotificationStore';
 import { useSnippetStore } from './SnippetStore';
 
-/** The inline `data` block of a parsed spec, if it carries `values`. */
-interface InlineData {
-  values: unknown;
-  format: DataFormat;
-}
+/** The path of the view whose `data` block Extract rewrites (`[]` = root). */
+type AnchorPath = ReadonlyArray<string | number>;
 
-/**
- * Read the top-level inline data from a draft spec's text, or null when there is
- * none (no snippet, unparseable, or no `data.values`). The format comes from an
- * explicit `data.format.type` when present (raw CSV/TSV strings), else JSON.
- */
-function readInlineData(draftText: string): InlineData | null {
-  let parsed: unknown;
+/** What confirm rewrites — an inline `data` block, or a self-defined `datasets` entry. */
+export type ExtractTarget =
+  | { kind: 'inline'; anchorPath: AnchorPath }
+  | { kind: 'self-defined'; datasetName: string };
+
+/** True when the active snippet's draft has data Extract can lift, in any view. */
+export function hasExtractableData(draftText: string): boolean {
   try {
-    parsed = JSON.parse(draftText);
+    return specHasExtractableData(JSON.parse(draftText));
   } catch {
-    return null;
+    return false;
   }
-  if (!parsed || typeof parsed !== 'object') return null;
-  const data = (parsed as Record<string, unknown>).data;
-  if (!data || typeof data !== 'object') return null;
-  const values = (data as Record<string, unknown>).values;
-  if (values === undefined) return null;
-  const declared = (data as Record<string, unknown>).format;
-  const type =
-    declared && typeof declared === 'object'
-      ? (declared as Record<string, unknown>).type
-      : undefined;
-  const format: DataFormat =
-    type === 'csv' || type === 'tsv' || type === 'topojson' ? type : 'json';
-  return { values, format };
-}
-
-/** True when the active snippet's draft has top-level inline data to extract. */
-export function hasInlineData(draftText: string): boolean {
-  return readInlineData(draftText) !== null;
 }
 
 export interface ExtractState {
   /** Proposed dataset name (required, unique). */
   name: string;
-  /** The inline data captured at open, for the read-only preview. */
-  source: InlineData | null;
+  /** The focused view's embedded data captured at open, for the read-only preview. */
+  source: InlinePayload | null;
+  /** Where `confirm` writes the by-name reference. */
+  target: ExtractTarget | null;
   /** Inline validation message, or null. */
   error: string | null;
 
-  /** Capture the active snippet's inline data and reset the form. */
-  init: () => void;
+  /** Seed the form with the focused view's captured data (extract-action). */
+  begin: (captured: { source: InlinePayload; target: ExtractTarget; name?: string }) => void;
   setName: (name: string) => void;
   /**
-   * Validate, create the dataset, and rewrite the active draft to reference it by
-   * name. Returns whether it committed; on failure `error` is set. `now`
-   * injectable for tests.
+   * Validate, create the dataset, and rewrite the spec to reference it by name.
+   * Returns whether it committed; on failure `error` is set. `now` injectable for
+   * tests.
    */
   confirm: (now?: Date) => boolean;
   reset: () => void;
 }
 
-const INITIAL = { name: '', source: null as InlineData | null, error: null as string | null };
+const INITIAL = {
+  name: '',
+  source: null as InlinePayload | null,
+  target: null as ExtractTarget | null,
+  error: null as string | null,
+};
 
 export const useExtractStore = create<ExtractState>((set, get) => ({
   ...INITIAL,
 
-  init: () => {
-    const draft = useSnippetStore.getState().draftText;
-    set({ name: '', source: readInlineData(draft), error: null });
-  },
+  begin: ({ source, target, name = '' }) => set({ name, source, target, error: null }),
 
   setName: (name) => set({ name, error: null }),
 
@@ -100,13 +94,42 @@ export const useExtractStore = create<ExtractState>((set, get) => ({
       set({ error: `A dataset named "${name}" already exists. Choose a different name.` });
       return false;
     }
-    const source = get().source;
-    if (!source) {
-      set({ error: 'No inline data to extract.' });
+    const { source, target } = get();
+    if (!source || !target) {
+      set({ error: 'No data to extract.' });
       return false;
     }
 
-    // JSON/TopoJSON store the parsed value; CSV/TSV keep raw text — but inline
+    // Resolve the rewrite before any side effect: parse the live draft and apply the
+    // target's rewrite to a fresh copy. Both can fail (the draft is no longer valid
+    // JSON, or its shape changed under the modal); bail with a message and create
+    // nothing rather than leave a half-done extraction.
+    const draftText = useSnippetStore.getState().draftText;
+    let spec: unknown;
+    try {
+      spec = JSON.parse(draftText);
+    } catch {
+      set({ error: 'The spec is no longer valid JSON. Close and reopen Extract.' });
+      return false;
+    }
+
+    let rewritten: unknown;
+    if (target.kind === 'inline') {
+      if (!setDataBindingAtPath(spec, target.anchorPath, { name })) {
+        set({ error: 'Could not locate the data to replace. Close and reopen Extract.' });
+        return false;
+      }
+      rewritten = spec;
+    } else {
+      const next = promoteSelfDefinedDataset(spec, target.datasetName, name);
+      if (!next) {
+        set({ error: 'Could not locate the data to replace. Close and reopen Extract.' });
+        return false;
+      }
+      rewritten = next;
+    }
+
+    // JSON/TopoJSON store the parsed value; CSV/TSV keep raw text — but the captured
     // `values` is already the right runtime shape for each, so store it directly.
     const dataset = createDataset({
       name,
@@ -117,20 +140,17 @@ export const useExtractStore = create<ExtractState>((set, get) => ({
     });
     useDatasetStore.getState().add(dataset);
 
-    // Rewrite the top-level data block to a by-name reference, preserving the rest
-    // of the spec and its pretty-printed text shape.
-    const draftText = useSnippetStore.getState().draftText;
-    const spec = JSON.parse(draftText) as Record<string, unknown>;
-    spec.data = { name };
-    useSnippetStore.getState().replaceActiveDraft(JSON.stringify(spec, null, 2), now);
+    // Re-serialize in the app's house style (json-format), preserving the spec and
+    // only swapping the captured data for the reference.
+    useSnippetStore.getState().replaceActiveDraft(formatSpec(rewritten), now);
 
-    // Success confirmation (spec §03F). Title states the action; the message
-    // adds the consequence — the spec was rewritten to reference the new dataset
-    // by name (council toast-copy rule, docs/architecture/10 → Toast copy).
+    // Success confirmation (spec §03F). Title states the action; the message adds
+    // the consequence — the spec was rewritten to reference the new dataset by name
+    // (council toast-copy rule, docs/architecture/10 → Toast copy).
     notify({
       kind: 'success',
       title: 'Dataset created',
-      message: `The spec now references "${name}" instead of its inline data.`,
+      message: `The spec now references "${name}" instead of its embedded data.`,
     });
     set(INITIAL);
     return true;

src/app/stores/SnippetStore.ts

@@ -114,7 +114,7 @@ export interface SnippetState {
   /**
    * Replace the active snippet's draft spec with new text and reload the editor
    * on the draft view (bumps `bufferEpoch`). Used by programmatic rewrites such
-   * as Extract-to-Dataset (spec §03F), which substitutes inline data for a
+   * as Extract-to-Dataset (spec §03F), which substitutes embedded data for a
    * by-name reference. No-op when no snippet is active. `now` injectable.
    */
   replaceActiveDraft: (text: string, now?: Date) => void;

src/core/spec-data.test.ts

@@ -1,5 +1,13 @@
 import { describe, expect, test } from 'vitest';
-import { classifyData, dataBindingAtPath, libraryRefName, selfDefinedNames } from './spec-data';
+import {
+  classifyData,
+  dataBindingAtPath,
+  forEachDataBinding,
+  libraryRefName,
+  mapDataBindings,
+  selfDefinedNames,
+  setDataBindingAtPath,
+} from './spec-data';
 
 describe('classifyData', () => {
   test('classifies the four Vega-Lite data shapes', () => {
@@ -108,3 +116,78 @@ describe('dataBindingAtPath', () => {
     expect(dataBindingAtPath({ mark: 'bar' }, ['mark', 'type', 'nope'])).toBeNull();
   });
 });
+
+describe('setDataBindingAtPath', () => {
+  test('sets the data block of the view at the anchor path', () => {
+    const spec = { layer: [{ mark: 'line', data: { values: [{ a: 1 }] } }] };
+    expect(setDataBindingAtPath(spec, ['layer', 0], { name: 'X' })).toBe(true);
+    expect(spec.layer[0].data).toEqual({ name: 'X' });
+  });
+
+  test('sets the root data block for the empty path', () => {
+    const spec: { data?: unknown; mark: string } = { mark: 'bar' };
+    expect(setDataBindingAtPath(spec, [], { name: 'Root' })).toBe(true);
+    expect(spec.data).toEqual({ name: 'Root' });
+  });
+
+  test('returns false when the path does not resolve to an object', () => {
+    const spec = { layer: [{ mark: 'line' }] };
+    expect(setDataBindingAtPath(spec, ['layer', 3], { name: 'X' })).toBe(false);
+    expect(setDataBindingAtPath({ mark: 'bar' }, ['mark'], { name: 'X' })).toBe(false);
+  });
+});
+
+describe('forEachDataBinding', () => {
+  test('visits every object node and prunes the data/datasets payloads', () => {
+    // A row inside `data.values` carries a field literally named `data`; the prune
+    // keeps the walk from visiting it as a binding.
+    const spec = {
+      datasets: { ds: [{ z: 1 }] },
+      layer: [{ data: { name: 'A' } }, { data: { values: [{ data: { name: 'buried' } }] } }],
+    };
+    const seen: unknown[] = [];
+    forEachDataBinding(spec, (node) => {
+      if (node.data !== undefined) seen.push(node.data);
+    });
+    expect(seen).toEqual([{ name: 'A' }, { values: [{ data: { name: 'buried' } }] }]);
+  });
+
+  test('passes the spec self-defined names and stops early on a true return', () => {
+    const spec = {
+      datasets: { ds: [{ a: 1 }] },
+      layer: [{ data: { name: 'ds' } }, { data: { name: 'other' } }],
+    };
+    let visits = 0;
+    let sawSelfDefined: ReadonlySet<string> | null = null;
+    forEachDataBinding(spec, (node, selfDefined) => {
+      visits++;
+      sawSelfDefined = selfDefined;
+      return node.data !== undefined; // stop at the first node carrying a data block
+    });
+    expect(sawSelfDefined && [...sawSelfDefined]).toEqual(['ds']);
+    // root (no data) → layer[0] (has data, stop). layer[1] never visited.
+    expect(visits).toBe(2);
+  });
+});
+
+describe('mapDataBindings', () => {
+  test('maps each data block, carries datasets through, and prunes payloads', () => {
+    const spec = {
+      datasets: { ds: [{ a: 1 }] },
+      layer: [{ data: { name: 'A' } }, { data: { values: [{ data: 'row-field' }] } }],
+    };
+    const out = mapDataBindings(spec, (data) =>
+      typeof (data as { name?: unknown }).name === 'string' ? { name: 'MAPPED' } : data,
+    ) as typeof spec;
+    expect(out.layer[0].data).toEqual({ name: 'MAPPED' });
+    expect(out.layer[1].data).toEqual({ values: [{ data: 'row-field' }] }); // payload untouched
+    expect(out.datasets).toEqual({ ds: [{ a: 1 }] }); // carried through
+  });
+
+  test('does not mutate the input', () => {
+    const spec = { data: { name: 'A' } };
+    const before = structuredClone(spec);
+    mapDataBindings(spec, () => ({ name: 'B' }));
+    expect(spec).toEqual(before);
+  });
+});

src/core/spec-data.ts

@@ -108,3 +108,90 @@ export function dataBindingAtPath(
   }
   return binding;
 }
+
+/**
+ * Set the `data` block of the view at `anchorPath` (an anchor from
+ * `dataBindingAtPath`), in place — the write-counterpart of the read above, used by
+ * Extract-to-Dataset to swap a view's inline data for a `{ name }` reference.
+ * Mutates `spec`, so the caller passes a copy it owns (a fresh parse). Returns false
+ * when the path no longer resolves to an object, so the caller can refuse rather
+ * than write the wrong node.
+ */
+export function setDataBindingAtPath(
+  spec: unknown,
+  anchorPath: ReadonlyArray<string | number>,
+  block: unknown,
+): boolean {
+  let node: unknown = spec;
+  for (const key of anchorPath) {
+    if (node === null || typeof node !== 'object') return false;
+    node = (node as Record<string | number, unknown>)[key];
+  }
+  if (node === null || typeof node !== 'object') return false;
+  (node as Record<string, unknown>).data = block;
+  return true;
+}
+
+/**
+ * The one spec walk every data-binding pass shares (reference detection/resolution,
+ * extraction gates). Visits each object node that could carry a `data` binding,
+ * with the spec's self-defined `datasets` names, and **prunes two payload keys** —
+ * a `data` object's contents and the top-level `datasets` map hold user data, not
+ * nested specs, so descending into them would misread a data row carrying a field
+ * literally named `data` as a binding. `visit` returns `true` to stop early (for a
+ * predicate); any other return continues. Pruning the same two keys here is what
+ * keeps every pass in agreement on what counts as a reference — they cannot drift
+ * because they share this walk.
+ */
+export function forEachDataBinding(
+  spec: unknown,
+  visit: (node: Record<string, unknown>, selfDefined: ReadonlySet<string>) => boolean | void,
+): void {
+  const selfDefined = selfDefinedNames(spec);
+  let stop = false;
+  const walk = (node: unknown): void => {
+    if (stop) return;
+    if (Array.isArray(node)) {
+      for (const item of node) walk(item);
+      return;
+    }
+    if (!isJsonObject(node)) return;
+    if (visit(node, selfDefined) === true) {
+      stop = true;
+      return;
+    }
+    for (const key of Object.keys(node)) {
+      if (key === 'data' || key === 'datasets') continue;
+      walk(node[key]);
+    }
+  };
+  walk(spec);
+}
+
+/**
+ * Return a deep copy of `spec` with each data binding's `data` value replaced by
+ * `mapData(data, selfDefined)` — the copy-rewrite counterpart of
+ * {@link forEachDataBinding}, for rename/promote passes. Prunes the same two keys:
+ * the top-level `datasets` map is carried through untouched, and a `data` payload is
+ * never descended into (only its block is mapped). The input is not mutated.
+ */
+export function mapDataBindings(
+  spec: unknown,
+  mapData: (data: unknown, selfDefined: ReadonlySet<string>) => unknown,
+): unknown {
+  const selfDefined = selfDefinedNames(spec);
+  const rewrite = (node: unknown): unknown => {
+    if (Array.isArray(node)) return node.map(rewrite);
+    if (node && typeof node === 'object') {
+      const out: Record<string, unknown> = {};
+      for (const [key, value] of Object.entries(node as Record<string, unknown>)) {
+        if (key === 'data') out[key] = mapData(value, selfDefined);
+        else if (key === 'datasets') out[key] = value;
+        else out[key] = rewrite(value);
+      }
+      return out;
+    }
+    return node;
+  };
+  return rewrite(spec);
+}

src/core/spec-inline-data.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it } from 'vitest';
-import { rowsForDataBinding } from './spec-inline-data';
+import {
+  inlineValuesOf,
+  rowsForDataBinding,
+  selfDefinedPayloadOf,
+  specHasExtractableData,
+} from './spec-inline-data';
 
 describe('rowsForDataBinding', () => {
   it('reads inline values from the given binding', () => {
@@ -21,3 +26,80 @@ describe('rowsForDataBinding', () => {
     expect(rowsForDataBinding({ mark: 'bar' }, { values: [] })).toBeNull(); // empty rows
   });
 });
+
+describe('inlineValuesOf', () => {
+  it('returns the JSON array payload as json', () => {
+    expect(inlineValuesOf({ values: [{ a: 1 }] })).toEqual({ values: [{ a: 1 }], format: 'json' });
+  });
+
+  it('preserves a CSV/TSV string payload verbatim with its declared format', () => {
+    expect(inlineValuesOf({ values: 'a,b\n1,2', format: { type: 'csv' } })).toEqual({
+      values: 'a,b\n1,2',
+      format: 'csv',
+    });
+    expect(inlineValuesOf({ values: 'a\tb', format: { type: 'tsv' } })).toEqual({
+      values: 'a\tb',
+      format: 'tsv',
+    });
+  });
+
+  it('keeps a name riding on inline values (named-inline is still inline)', () => {
+    expect(inlineValuesOf({ name: 'x', values: [{ a: 1 }] })).toEqual({
+      values: [{ a: 1 }],
+      format: 'json',
+    });
+  });
+
+  it('returns null for a library reference, url, generator, or non-object', () => {
+    expect(inlineValuesOf({ name: 'sales' })).toBeNull();
+    expect(inlineValuesOf({ url: 'x.csv' })).toBeNull();
+    expect(inlineValuesOf({ sequence: { start: 0, stop: 5 } })).toBeNull();
+    expect(inlineValuesOf(null)).toBeNull();
+  });
+});
+
+describe('selfDefinedPayloadOf', () => {
+  it('returns the rows of a referenced self-defined datasets entry', () => {
+    const spec = { datasets: { sales: [{ a: 1 }, { a: 2 }] }, data: { name: 'sales' } };
+    expect(selfDefinedPayloadOf(spec, spec.data)).toEqual({
+      values: [{ a: 1 }, { a: 2 }],
+      format: 'json',
+    });
+  });
+
+  it('returns null for a library reference, inline values, or a non-array entry', () => {
+    const spec = { datasets: { sales: [{ a: 1 }] } };
+    expect(selfDefinedPayloadOf(spec, { name: 'LibraryRef' })).toBeNull(); // not self-defined
+    expect(selfDefinedPayloadOf(spec, { values: [{ a: 1 }] })).toBeNull(); // inline, not named
+    expect(
+      selfDefinedPayloadOf({ datasets: { s: 'a,b\n1,2' }, data: {} }, { name: 's' }),
+    ).toBeNull();
+  });
+});
+
+describe('specHasExtractableData', () => {
+  it('is true for inline values and for a self-defined reference', () => {
+    expect(specHasExtractableData({ data: { values: [{ a: 1 }] } })).toBe(true);
+    expect(specHasExtractableData({ datasets: { ds: [{ a: 1 }] }, data: { name: 'ds' } })).toBe(
+      true,
+    );
+  });
+
+  it('is false for a library reference, url, or generator', () => {
+    expect(specHasExtractableData({ data: { name: 'sales' } })).toBe(false);
+    expect(specHasExtractableData({ data: { url: 'x.csv' } })).toBe(false);
+    expect(specHasExtractableData({ data: { sequence: { start: 0, stop: 5 } } })).toBe(false);
+  });
+
+  it('ignores a field literally named data inside a user data row (prune-the-payload)', () => {
+    // The walker prunes the `data`/`datasets` keys, so a row that carries a field
+    // named `data` is never mistaken for a binding — only the genuine top-level
+    // inline binding triggers, and an encoding field named `data` triggers nothing.
+    expect(
+      specHasExtractableData({ data: { values: [{ data: { name: 'x' } }] }, mark: 'bar' }),
+    ).toBe(true);
+    expect(
+      specHasExtractableData({ layer: [{ mark: 'bar', encoding: { x: { field: 'data' } } }] }),
+    ).toBe(false);
+  });
+});

src/core/spec-inline-data.ts

@@ -1,18 +1,23 @@
 /**
  * Inline data carried by a spec (docs/architecture/08 → editor augmentation).
  *
- * Portable core. When a view binds no named library dataset, its columns still
- * exist — inline, in `data.values` or a self-defined top-level `datasets` entry.
- * This pulls those rows out so the editor can profile them (core/profile) and offer
- * the same field hints a library-bound view gets — a "ghost dataset" derived from
- * the spec itself, with nothing stored.
+ * Portable core. Two readers over a view's inline data:
  *
- * URL data has no rows to read statically, and `values` given as a CSV/TSV string
- * needs format-aware parsing — both out of scope here (they yield null).
+ *   - `rowsForDataBinding` pulls **profileable JSON rows** out so the editor can
+ *     profile them (core/profile) and offer the same field hints a library-bound
+ *     view gets — a "ghost dataset" derived from the spec, with nothing stored.
+ *     URL data has no rows to read statically, and a CSV/TSV string `values`
+ *     payload needs format-aware parsing — both out of scope there (they yield null).
+ *   - `inlineValuesOf` / `selfDefinedPayloadOf` pull the **raw payload** (values +
+ *     format) Extract-to-Dataset lifts whole into a stored dataset — from a view's
+ *     inline `values` (kept verbatim, so a CSV/TSV string survives) or from a
+ *     self-defined `datasets` entry the view references by name. `specHasExtractableData`
+ *     is the gate Extract reads to decide whether any view carries data it can lift.
  */
 
+import type { DataFormat } from './format-detection';
 import { isJsonObject } from './spec-config';
-import { classifyData, selfDefinedNames } from './spec-data';
+import { classifyData, forEachDataBinding, selfDefinedNames } from './spec-data';
 
 /** An array of row objects, or null when the value is not tabular inline data. */
 function asRows(value: unknown): Record<string, unknown>[] | null {
@@ -42,3 +47,74 @@ export function rowsForDataBinding(spec: unknown, data: unknown): Record<string,
   }
   return null;
 }
+
+/** The raw inline payload of a `data` block, or null when it is not inline data. */
+export interface InlinePayload {
+  /** The block's `values` verbatim — a JSON array OR a raw CSV/TSV/topojson string. */
+  values: unknown;
+  /** The format declared by `data.format.type`, defaulting to JSON. */
+  format: DataFormat;
+}
+
+/**
+ * The inline payload a `data` block carries — its `values` and declared format —
+ * or null when the block is not inline (`classifyData` ≠ `'inline'`). Unlike
+ * {@link rowsForDataBinding}, which profiles JSON rows and rejects a CSV/TSV
+ * string, this preserves the payload **verbatim**: it is what Extract-to-Dataset
+ * lifts into a stored dataset, and a raw CSV/TSV string is already the right
+ * runtime shape to store. The format reads an explicit `data.format.type`
+ * (csv/tsv/topojson), defaulting to json (a plain array of row objects).
+ */
+export function inlineValuesOf(data: unknown): InlinePayload | null {
+  if (classifyData(data) !== 'inline') return null;
+  const block = data as { values: unknown; format?: unknown };
+  const type = isJsonObject(block.format) ? block.format.type : undefined;
+  const format: DataFormat =
+    type === 'csv' || type === 'tsv' || type === 'topojson' ? type : 'json';
+  return { values: block.values, format };
+}
+
+/**
+ * The payload of a view's reference to a *self-defined* dataset — a `{ name }`
+ * block whose name the spec defines for itself via top-level `datasets`. This is
+ * the spec's own embedded data in a different shape (the rows live in the
+ * `datasets` map, not in a `data.values` block), so Extract can lift it too. Only a
+ * JSON-array `datasets` entry is liftable here; a string payload (rare) yields null
+ * and is left for a future pass. Returns null when `data` is not a self-defined
+ * reference. The library-reference case (`{ name }` not self-defined) is already a
+ * stored dataset — nothing to extract — and also yields null.
+ */
+export function selfDefinedPayloadOf(spec: unknown, data: unknown): InlinePayload | null {
+  if (classifyData(data) !== 'named') return null;
+  const { name } = data as { name: string };
+  if (!isJsonObject(spec) || !isJsonObject(spec.datasets) || !selfDefinedNames(spec).has(name)) {
+    return null;
+  }
+  const entry = (spec.datasets as Record<string, unknown>)[name];
+  return Array.isArray(entry) ? { values: entry, format: 'json' } : null;
+}
+
+/**
+ * Whether any view binds data Extract can lift — the gate that decides if
+ * Extract-to-Dataset is offered. That is inline `values` **or** a reference to a
+ * self-defined `datasets` entry (the spec's own embedded data, in either shape). A
+ * library reference, a url, or a generator carries nothing to lift. Runs over the
+ * shared `forEachDataBinding` walk, stopping at the first liftable binding.
+ */
+export function specHasExtractableData(spec: unknown): boolean {
+  let found = false;
+  forEachDataBinding(spec, (node, selfDefined) => {
+    const data = node.data;
+    const kind = classifyData(data);
+    if (
+      kind === 'inline' ||
+      (kind === 'named' &&
+        typeof (data as { name?: unknown }).name === 'string' &&
+        selfDefined.has((data as { name: string }).name))
+    ) {
+      found = true;
+      return true; // stop at the first match
+    }
+  });
+  return found;
+}

src/core/spec-refs.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, test } from 'vitest';
-import { extractDatasetRefs, recomputeDatasetRefs, renameDatasetInSpec } from './spec-refs';
+import {
+  extractDatasetRefs,
+  promoteSelfDefinedDataset,
+  recomputeDatasetRefs,
+  renameDatasetInSpec,
+} from './spec-refs';
 
 describe('extractDatasetRefs', () => {
   test('collects a top-level named-data reference', () => {
@@ -161,3 +166,55 @@ describe('renameDatasetInSpec', () => {
     expect(out.transform[0].from.data.name).toBe('New');
   });
 });
+
+describe('promoteSelfDefinedDataset', () => {
+  test('keeping the name drops the datasets entry and leaves references intact', () => {
+    const spec = { datasets: { sales: [{ a: 1 }] }, data: { name: 'sales' }, mark: 'bar' };
+    const out = promoteSelfDefinedDataset(spec, 'sales', 'sales')!;
+    expect(out.datasets).toBeUndefined(); // map emptied → removed
+    expect(out.data).toEqual({ name: 'sales' }); // reference un-shadows onto the library
+  });
+
+  test('renaming rewrites every reference and keeps sibling datasets entries', () => {
+    const spec = {
+      datasets: { sales: [{ a: 1 }], other: [{ b: 2 }] },
+      layer: [
+        { data: { name: 'sales' } },
+        { data: { name: 'sales' } },
+        { data: { name: 'other' } },
+      ],
+    };
+    const out = promoteSelfDefinedDataset(spec, 'sales', 'Sales 2024')!;
+    expect(out.layer).toEqual([
+      { data: { name: 'Sales 2024' } },
+      { data: { name: 'Sales 2024' } },
+      { data: { name: 'other' } },
+    ]);
+    expect(out.datasets).toEqual({ other: [{ b: 2 }] });
+  });
+
+  test('does not touch a named-inline block that happens to share the name', () => {
+    // `{ name, values }` is its own inline data, not a datasets reference.
+    const spec = {
+      datasets: { sales: [{ a: 1 }] },
+      layer: [{ data: { name: 'sales' } }, { data: { name: 'sales', values: [{ z: 9 }] } }],
+    };
+    const out = promoteSelfDefinedDataset(spec, 'sales', 'New')!;
+    expect(out.layer).toEqual([
+      { data: { name: 'New' } }, // the reference
+      { data: { name: 'sales', values: [{ z: 9 }] } }, // inline — left alone
+    ]);
+  });
+
+  test('returns null when the name is not a self-defined dataset', () => {
+    expect(promoteSelfDefinedDataset({ data: { name: 'sales' } }, 'sales', 'New')).toBeNull();
+    expect(promoteSelfDefinedDataset({ datasets: { a: [{}] } }, 'missing', 'New')).toBeNull();
+  });
+
+  test('does not mutate the input', () => {
+    const spec = { datasets: { sales: [{ a: 1 }] }, data: { name: 'sales' } };
+    const before = structuredClone(spec);
+    promoteSelfDefinedDataset(spec, 'sales', 'New');
+    expect(spec).toEqual(before);
+  });
+});

src/core/spec-refs.ts

@@ -30,7 +30,8 @@
  * the recursive walk never has to care.
  */
 
-import { libraryRefName, selfDefinedNames } from './spec-data';
+import { isJsonObject } from './spec-config';
+import { classifyData, forEachDataBinding, libraryRefName, mapDataBindings } from './spec-data';
 
 type Json = unknown;
 
@@ -50,30 +51,11 @@ function safeParse(s: string): Json {
  */
 export function extractDatasetRefs(spec: Json): string[] {
   const root = typeof spec === 'string' ? safeParse(spec) : spec;
-  const selfDefined = selfDefinedNames(root);
   const names = new Set<string>();
-
-  const walk = (node: Json): void => {
-    if (Array.isArray(node)) {
-      for (const item of node) walk(item);
-      return;
-    }
-    if (node && typeof node === 'object') {
-      const obj = node as Record<string, Json>;
-      const refName = libraryRefName(obj.data, selfDefined);
+  forEachDataBinding(root, (node, selfDefined) => {
+    const refName = libraryRefName(node.data, selfDefined);
     if (refName !== null) names.add(refName);
-      // Recurse into every key except the two that hold data payloads (`data` —
-      // classified above; `datasets` — the spec's own inline data). Pruning them
-      // keeps the walk out of user data rows, where a field named `data` would
-      // otherwise be misread as a reference. Kept in step with rendering.ts.
-      for (const key of Object.keys(obj)) {
-        if (key === 'data' || key === 'datasets') continue;
-        walk(obj[key]);
-      }
-    }
-  };
-
-  walk(root);
+  });
   return [...names];
 }
 
@@ -98,34 +80,64 @@ export function renameDatasetInSpec<T>(spec: T, oldName: string, newName: string
   // Unparseable text → return it unchanged (nothing resolvable to rewrite).
   if (isString && root === null) return spec;
 
-  const selfDefined = selfDefinedNames(root);
-
-  const rewrite = (node: Json): Json => {
-    if (Array.isArray(node)) return node.map(rewrite);
-    if (node && typeof node === 'object') {
-      const out: Record<string, Json> = {};
-      for (const [k, v] of Object.entries(node as Record<string, Json>)) {
-        // A `data` block is a reference site, not a container: rename it when it is
-        // a library reference to `oldName`, and never recurse into its payload. A
-        // `datasets` map is the spec's own inline data: leave it whole. Pruning
-        // both (mirroring extractDatasetRefs) keeps rename out of user data rows,
-        // where a field named `data` would otherwise be rewritten as a reference.
-        if (k === 'data') {
-          out[k] =
-            libraryRefName(v, selfDefined) === oldName
-              ? { ...(v as Record<string, Json>), name: newName }
-              : v;
-        } else if (k === 'datasets') {
-          out[k] = v;
-        } else {
-          out[k] = rewrite(v);
-        }
-      }
-      return out;
-    }
-    return node;
-  };
-
-  const rewritten = rewrite(root);
+  // Rewrite only a `data` block that is a library reference to `oldName`; native
+  // data carrying the name as a label and a self-defined `datasets` key are left
+  // alone (the shared walk prunes the payload keys).
+  const rewritten = mapDataBindings(root, (data, selfDefined) =>
+    libraryRefName(data, selfDefined) === oldName
+      ? { ...(data as Record<string, Json>), name: newName }
+      : data,
+  );
   return (isString ? JSON.stringify(rewritten, null, 2) : rewritten) as T;
 }
+
+/**
+ * Promote a self-defined dataset to a stored library reference — the rewrite behind
+ * Extract-to-Dataset for the `datasets.<name>` case (docs/architecture/07 §3.2).
+ *
+ * A view that binds `{ "data": { "name": X } }` where the spec defines `X` for
+ * itself via top-level `datasets` is referencing the spec's *own* embedded data.
+ * Once that data is saved to the library, the `datasets` entry must go so the same
+ * `{ name }` reference resolves to the stored dataset instead. This returns a copy
+ * of `spec` with:
+ *   - every self-defined `{ name: oldName }` data block renamed to `newName` (a
+ *     no-op when the name is unchanged, in which case the reference simply
+ *     un-shadows onto the new library dataset of the same name); and
+ *   - the `datasets[oldName]` entry removed (and the whole `datasets` map removed
+ *     when it empties).
+ *
+ * Returns `null` when `oldName` is not actually a self-defined dataset, so the
+ * caller extracts nothing. The input is never mutated. (Parallel to
+ * `renameDatasetInSpec`, but it targets *named* references by name rather than
+ * *library* references via `libraryRefName` — self-defined names are exactly the
+ * ones the latter excludes.)
+ */
+export function promoteSelfDefinedDataset(
+  spec: unknown,
+  oldName: string,
+  newName: string,
+): Record<string, Json> | null {
+  if (!isJsonObject(spec) || !isJsonObject(spec.datasets) || !(oldName in spec.datasets)) {
+    return null;
+  }
+
+  // Rename every named reference to oldName (a `data` block carrying `values`/`url`
+  // is its own data, not a `datasets` reference, so classify first). A same-name
+  // promotion needs no rewrite — the reference un-shadows onto the new library
+  // dataset once the entry below is gone.
+  const renamed = (
+    newName === oldName
+      ? { ...spec }
+      : mapDataBindings(spec, (data) =>
+          classifyData(data) === 'named' && (data as { name: string }).name === oldName
+            ? { ...(data as Record<string, Json>), name: newName }
+            : data,
+        )
+  ) as Record<string, Json>;
+
+  const datasets = { ...(renamed.datasets as Record<string, Json>) };
+  delete datasets[oldName];
+  if (Object.keys(datasets).length === 0) delete renamed.datasets;
+  else renamed.datasets = datasets;
+  return renamed;
+}