Eng-council sweep: export hygiene, dead code, helper dedup, declare vega-expression

src/core/chart-builder.ts

@@ -34,8 +34,7 @@ export const MARK_TYPES = ['bar', 'line', 'point', 'area', 'circle'] as const;
 export type MarkType = (typeof MARK_TYPES)[number];
 
 /** The four Vega-Lite field types a channel may carry, in override-menu order. */
-export const FIELD_TYPES = ['quantitative', 'nominal', 'ordinal', 'temporal'] as const;
-export type FieldType = (typeof FIELD_TYPES)[number];
+export type FieldType = 'quantitative' | 'nominal' | 'ordinal' | 'temporal';
 
 /** The four encoding channels the builder offers, in display order (spec §06). */
 export const CHANNELS = ['x', 'y', 'color', 'size'] as const;
@@ -49,8 +48,7 @@ export type ChannelName = (typeof CHANNELS)[number];
  * reduce a quantitative field; min/max also order a temporal or ordinal one. See
  * `validAggregateOps` for the per-type menu.
  */
-export const AGGREGATE_OPS = ['count', 'distinct', 'sum', 'mean', 'median', 'min', 'max'] as const;
-export type AggregateOp = (typeof AGGREGATE_OPS)[number];
+export type AggregateOp = 'count' | 'distinct' | 'sum' | 'mean' | 'median' | 'min' | 'max';
 
 /**
  * Temporal granularities (Vega-Lite `timeUnit`), coarse → fine, with the combined
@@ -71,12 +69,10 @@ export const TIME_UNITS = [
 export type TimeUnit = (typeof TIME_UNITS)[number];
 
 /** Sort the categorical axis by its measure (spec §06 → Ranking). */
-export const SORT_ORDERS = ['ascending', 'descending'] as const;
-export type SortOrder = (typeof SORT_ORDERS)[number];
+export type SortOrder = 'ascending' | 'descending';
 
 /** Part-to-whole stacking for bar/area + a colour series: absolute vs 100%. */
-export const STACK_MODES = ['zero', 'normalize'] as const;
-export type StackMode = (typeof STACK_MODES)[number];
+export type StackMode = 'zero' | 'normalize';
 
 /**
  * Comparison operators a guarded filter predicate offers (Vega-Lite field
@@ -85,17 +81,7 @@ export type StackMode = (typeof STACK_MODES)[number];
  * `range`; a category offers membership (`oneOf`). `notEqual` is expressed as a
  * `{ not: { …equal } }` logical wrapper (Vega-Lite has no bare `!=` predicate).
  */
-export const FILTER_OPS = [
-  'equal',
-  'notEqual',
-  'lt',
-  'lte',
-  'gt',
-  'gte',
-  'range',
-  'oneOf',
-] as const;
-export type FilterOp = (typeof FILTER_OPS)[number];
+export type FilterOp = 'equal' | 'notEqual' | 'lt' | 'lte' | 'gt' | 'gte' | 'range' | 'oneOf';
 
 /** How a filter expresses its predicate: a guarded shelf, or a raw expression. */
 export type FilterMode = 'predicate' | 'expression';

src/core/dataset.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, test } from 'vitest';
 import {
+  cellText,
   computeDatasetProfile,
   CURRENT_DATASET_VERSION,
   createDataset,
@@ -153,6 +154,17 @@ describe('tabularRows', () => {
   });
 });
 
+describe('cellText', () => {
+  test('strings as-is, null/undefined blank, others as JSON (no "[object Object]")', () => {
+    expect(cellText('plain')).toBe('plain');
+    expect(cellText(null)).toBe('');
+    expect(cellText(undefined)).toBe('');
+    expect(cellText(42)).toBe('42');
+    expect(cellText(false)).toBe('false');
+    expect(cellText({ a: 1 })).toBe('{"a":1}');
+  });
+});
+
 describe('snapshotFromText', () => {
   test('JSON content is parsed and typed json (content beats extension)', () => {
     const { data, format } = snapshotFromText('[{"a":1}]', 'https://x/data.txt');

src/core/dataset.ts

@@ -235,6 +235,16 @@ export function tabularRows(
   return limit != null && limit >= 0 && rows.length > limit ? rows.slice(0, limit) : rows;
 }
 
+/**
+ * Render a `tabularRows` cell for a preview table: strings as-is, null/undefined
+ * empty, anything else (numbers, booleans, nested values) as compact JSON.
+ */
+export function cellText(value: unknown): string {
+  if (value == null) return '';
+  if (typeof value === 'string') return value;
+  return JSON.stringify(value);
+}
+
 /**
  * Orchestrate profiling for a dataset payload: compute `size` (always), decide
  * tabular vs N/A by format, and delegate to `profileData`. Identical for inline

src/core/expr-validate.ts

@@ -9,8 +9,8 @@
  * grammar. It also extracts the `datum.<field>` references so the UI can flag a typo
  * against the dataset's actual columns before the chart silently renders empty.
  *
- * `vega-expression` is a pure dependency already in the bundle (Vega pulls it in for
- * rendering), so importing it here adds nothing and keeps this module browser-free.
+ * `vega-expression` is declared as a direct dependency but adds no bundle weight —
+ * Vega already ships it for rendering; this import reuses the same copy.
  */
 
 import { parseExpression } from 'vega-expression';

src/core/format-detection.ts

@@ -10,7 +10,7 @@
  */
 
 export type DataFormat = 'json' | 'csv' | 'tsv' | 'topojson';
-export type DetectionConfidence = 'high' | 'medium' | 'low';
+type DetectionConfidence = 'high' | 'medium' | 'low';
 
 export interface FormatDetection {
   format: DataFormat | null;

src/core/json-format.ts

@@ -12,7 +12,7 @@
 import stringify from 'json-stringify-pretty-compact';
 
 /** Width budget before an array/object wraps onto multiple lines. */
-export const DEFAULT_MAX_LINE = 80;
+const DEFAULT_MAX_LINE = 80;
 
 /** Default indent (spaces) — matches the editor's default tab size (spec §07). */
 const DEFAULT_INDENT = 2;

src/core/profile.ts

@@ -21,7 +21,7 @@
 
 import { inferColumnType, isEmpty, isNumeric, type ColumnType } from './type-inference';
 
-export interface ColumnTypeInfo {
+interface ColumnTypeInfo {
   /** The column name. */
   name: string;
   /** The inferred display type for the column. */

src/core/storage-estimate.ts

@@ -16,7 +16,7 @@
  */
 
 /** A category of stored data and its measured size in bytes. */
-export interface StorageSegment {
+interface StorageSegment {
   key: 'snippets' | 'datasets' | 'app';
   /** User-facing label, centralized here so the component stays presentational. */
   label: string;

src/core/vega-themes.ts

@@ -181,7 +181,7 @@ const PRESET_IDS = [
   'dark',
 ] as const;
 
-export type ChartThemePresetId = (typeof PRESET_IDS)[number];
+type ChartThemePresetId = (typeof PRESET_IDS)[number];
 
 /** Empty config — the stock sentinel resolves to "inject nothing". */
 const STOCK_CONFIG: Config = {};