camdecoster · Sep 4, 2026 · Sep 2, 2026 · Sep 2, 2026 · Sep 2, 2026 · Sep 2, 2026
diff --git a/draftlogs/8010_fix.md b/draftlogs/8010_fix.md
@@ -0,0 +1 @@
+- Handle regex enum values when generating schema types [[#8010](https://github.com/plotly/plotly.js/pull/8010)]
diff --git a/lib/index.d.ts b/lib/index.d.ts
@@ -27,6 +27,8 @@ export as namespace Plotly;
 // ---------------------------------------------------------------------------
 
 export type {
+    AxisName,
+    CartesianSubplotId,
     Color,
     ColorScale,
     Datum,
@@ -36,7 +38,9 @@ export type {
     MarkerSymbol,
     TypedArray,
     XAnchor,
-    YAnchor
+    XAxisName,
+    YAnchor,
+    YAxisName
 } from '../src/types/lib/common';
 
 // ---------------------------------------------------------------------------
@@ -50,15 +54,12 @@ export type * from '../src/types/generated/schema';
 // ---------------------------------------------------------------------------
 
 export type {
-    AxisName,
     ButtonClickEvent,
     Icon,
     ModeBarButton,
     ModeBarButtonAny,
     ModeBarDefaultButtons,
-    Template,
-    XAxisName,
-    YAxisName
+    Template
 } from '../src/types/core/layout';
 
 // ---------------------------------------------------------------------------

diff --git a/src/types/ARCHITECTURE.md b/src/types/ARCHITECTURE.md
@@ -111,11 +111,11 @@ src/types/
 │   ├── data.internal.d.ts        # CalcData, FullData
 │   ├── events.d.ts               # PlotMouseEvent, PlotlyHTMLElement, etc.
 │   ├── graph-div.internal.d.ts   # GraphDiv, GraphContext
-│   ├── layout.d.ts               # AxisName, ModeBar behavioral types, Template
+│   ├── layout.d.ts               # ModeBar behavioral types, Template
 │   └── layout.internal.d.ts      # FullLayout, LayoutSize, SubplotInfo
 │
 ├── lib/                          # primitives + the schema-extraction machinery
-│   ├── common.d.ts               # Color, Datum, TypedArray, MarkerSymbol, ...
+│   ├── common.d.ts               # Color, Datum, TypedArray, AxisName, ...
 │   └── attributes.d.ts           # AttributeMap, AttrInfo (compile-time validation)
 │
 └── generated/                    # machine-generated types

diff --git a/src/types/core/layout.d.ts b/src/types/core/layout.d.ts
@@ -12,24 +12,10 @@ import type { Data, Layout, TraceType } from '../generated/schema';
 import type { PlotlyHTMLElement } from './events';
 
 // ---------------------------------------------------------------------------
-// Axis name types (template literal utilities — not in schema)
+// Axis name types
 // ---------------------------------------------------------------------------
 
-/**
- * Numeric axis suffix plus the optional ` domain` qualifier. The suffix is
- * empty for the first axis (`x` / `y`) and `2` through `99` otherwise.
- */
-type xYAxisNames = `${
-    | ''
-    | `${2 | 3 | 4 | 5 | 6 | 7 | 8 | 9}`
-    | `${1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9}${0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9}`}${'' | ' domain'}`;
-
-/** Any valid x-axis reference: `'x'`, `'x2'`, …, `'x99'`, optionally `' domain'`. */
-export type XAxisName = `x${xYAxisNames}`;
-/** Any valid y-axis reference: `'y'`, `'y2'`, …, `'y99'`, optionally `' domain'`. */
-export type YAxisName = `y${xYAxisNames}`;
-/** Any valid axis reference (x or y, numbered or not, domain-qualified or not). */
-export type AxisName = XAxisName | YAxisName;
+export type { AxisName, CartesianSubplotId, XAxisName, YAxisName } from '../lib/common';
 
 // ---------------------------------------------------------------------------
 // ModeBar / Icon (behavioral types — not in schema)
@@ -169,4 +155,3 @@ export interface Template {
     /** Template layout defaults. */
     layout?: Partial<Layout> | undefined;
 }
-
diff --git a/src/types/generated/schema.d.ts b/src/types/generated/schema.d.ts
diff --git a/src/types/lib/common.d.ts b/src/types/lib/common.d.ts
@@ -64,6 +64,52 @@ export type XAnchor = 'auto' | 'left' | 'center' | 'right';
 /** Vertical anchor position for components (legend, annotation, etc.). */
 export type YAnchor = 'auto' | 'top' | 'middle' | 'bottom';
 
+// ---------------------------------------------------------------------------
+// Axis and subplot identifiers
+//
+// The schema states these as regexes, which no TypeScript type can express
+// exactly. The template literal types below enumerate the accepted strings
+// instead, so they are bounded where the schema is not. See the digit-tier
+// note on `AxisNumber`.
+//
+// tasks/generate_schema_types.mjs maps each schema regex onto one of these
+// types through its REGEX_VALUE_TYPES table.
+// ---------------------------------------------------------------------------
+
+type Digit = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9;
+type NonZeroDigit = 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9;
+
+/**
+ * Numeric axis suffix. Empty for the first axis (`x` / `y`), then `2` through
+ * `999`. There is no `1` suffix — the first axis is unnumbered.
+ *
+ * The schema regex accepts any number of digits. This type stops at three
+ * because a template literal union has to be finite, so charts with 1000 or
+ * more axes of one letter cannot be typed.
+ */
+type AxisNumber = '' | `${Exclude<NonZeroDigit, 1>}` | `${NonZeroDigit}${Digit}` | `${NonZeroDigit}${Digit}${Digit}`;
+
+/**
+ * Two-digit variant of `AxisNumber`, capped at `99`.
+ *
+ * Used only where the suffix appears twice in one identifier. Three digits
+ * squared exceeds the TypeScript union size limit.
+ */
+type ShortAxisNumber = '' | `${Exclude<NonZeroDigit, 1>}` | `${NonZeroDigit}${Digit}`;
+
+/** Any valid x-axis reference: `'x'`, `'x2'`, …, optionally `' domain'`. */
+export type XAxisName = `x${AxisNumber}${'' | ' domain'}`;
+/** Any valid y-axis reference: `'y'`, `'y2'`, …, optionally `' domain'`. */
+export type YAxisName = `y${AxisNumber}${'' | ' domain'}`;
+/** Any valid axis reference (x or y, numbered or not, domain-qualified or not). */
+export type AxisName = XAxisName | YAxisName;
+
+/**
+ * A cartesian subplot id pairing an x and a y axis, such as `'xy'` or
+ * `'x3y2'`. Unlike `XAxisName`, no `' domain'` qualifier is permitted.
+ */
+export type CartesianSubplotId = `x${ShortAxisNumber}y${ShortAxisNumber}`;
+
 // ---------------------------------------------------------------------------
 // Error bars
 // ---------------------------------------------------------------------------

diff --git a/tasks/generate_schema_types.mjs b/tasks/generate_schema_types.mjs
@@ -194,6 +194,53 @@ function serializeValue(v) {
     return String(v); // numbers, booleans
 }
 
+/**
+ * Schema `values` entries wrapped in `/.../` are regexes, not literals. The
+ * enumerated `validateFunction` in src/lib/coerce.js unwraps and tests them.
+ * Each one maps to a template literal type in src/types/lib/common.d.ts that
+ * accepts the same strings.
+ *
+ * A regex stands in for a value set that the static schema cannot list,
+ * because the real set depends on how many axes a figure declares.
+ */
+const REGEX_VALUE_TYPES = new Map([
+    ['/^x([2-9]|[1-9][0-9]+)?( domain)?$/', 'XAxisName'],
+    ['/^y([2-9]|[1-9][0-9]+)?( domain)?$/', 'YAxisName'],
+    ['/^x([2-9]|[1-9][0-9]+)?y([2-9]|[1-9][0-9]+)?$/', 'CartesianSubplotId']
+]);
+
+/** Test whether a schema value uses the `/.../` regex convention. */
+function isRegexValue(v) {
+    return typeof v === 'string' && v.length > 1 && v.startsWith('/') && v.endsWith('/');
+}
+
+/**
+ * Serialize one `values` entry from a string or enumerated attribute.
+ *
+ * Plain values become string literals. Regex values become the named type
+ * that accepts the same strings.
+ *
+ * @param {string|number|boolean} v - The schema value
+ * @param {string} attrPath - Dotted attribute path, used in the error message
+ * @returns {string}
+ * @throws If `v` is a regex with no entry in `REGEX_VALUE_TYPES`. Emitting the
+ *   regex source as a string literal would produce a type that only accepts
+ *   the pattern text, so failing here is deliberate.
+ */
+function enumValueToTS(v, attrPath) {
+    if (!isRegexValue(v)) return serializeValue(v);
+
+    const typeName = REGEX_VALUE_TYPES.get(v);
+    if (!typeName) {
+        throw new Error(
+            `Unmapped regex value '${v}' at '${attrPath}'. Add an entry to REGEX_VALUE_TYPES ` +
+                `pointing at a template literal type in src/types/lib/common.d.ts that accepts ` +
+                `the same strings.`
+        );
+    }
+    return typeName;
+}
+
 /**
  * Try to match a values array to a known common type.
  * Returns the type name string or null.
@@ -215,32 +262,42 @@ function matchCommonType(values) {
  * When all elements share the same valType we can emit a precise tuple
  * or array type instead of `unknown[]`.
  */
-function infoArrayToTS(attr) {
+function infoArrayToTS(attr, attrPath) {
     if (!attr.items) return 'any[]';
 
     // items can be an array of item descriptors or a single descriptor
     // (single descriptor = freeLength homogeneous array)
     if (!Array.isArray(attr.items)) {
-        const elemType = simpleValType(attr.items.valType);
-        return `${elemType}[]`;
+        return `${asArrayElement(simpleValType(attr.items, attrPath))}[]`;
     }
 
-    const elemTypes = attr.items.map((item) => simpleValType(item.valType));
+    const elemTypes = attr.items.map((item) => simpleValType(item, attrPath));
 
     if (attr.freeLength) {
         // Variable-length — use array of the union of element types
         const unique = [...new Set(elemTypes)];
         const union = unique.length === 1 ? unique[0] : unique.join(' | ');
-        return `${union}[]`;
+        return `${asArrayElement(union)}[]`;
     }
 
     // Fixed-length — emit tuple
     return `[${elemTypes.join(', ')}]`;
 }
 
-/** Map a valType string to a simple TS type (no arrayOk handling). */
-function simpleValType(valType) {
-    switch (valType) {
+/** Parenthesize a union so that appending `[]` binds to the whole union. */
+function asArrayElement(type) {
+    return type.includes('|') ? `(${type})` : type;
+}
+
+/**
+ * Map an info_array item descriptor to a simple TS type (no arrayOk handling).
+ *
+ * @param {object} item - The item descriptor, carrying at least `valType`
+ * @param {string} attrPath - Dotted path of the owning attribute
+ * @returns {string}
+ */
+function simpleValType(item, attrPath) {
+    switch (item.valType) {
         case 'number':
         case 'integer':
             return 'number';
@@ -251,6 +308,9 @@ function simpleValType(valType) {
             return 'boolean';
         case 'color':
             return 'Color';
+        case 'enumerated':
+            if (!Array.isArray(item.values)) return 'any';
+            return item.values.map((v) => enumValueToTS(v, attrPath)).join(' | ');
         default:
             return 'any';
     }
@@ -368,7 +428,7 @@ function valTypeToTS(attr, attrPath) {
                     base = common;
                     break;
                 }
-                base = attr.values.map(serializeValue).join(' | ');
+                base = attr.values.map((v) => enumValueToTS(v, attrPath)).join(' | ');
             } else {
                 base = 'string';
             }
@@ -405,7 +465,7 @@ function valTypeToTS(attr, attrPath) {
                     base = common;
                     break;
                 }
-                base = attr.values.map(serializeValue).join(' | ');
+                base = attr.values.map((v) => enumValueToTS(v, attrPath)).join(' | ');
             } else {
                 base = 'any';
             }
@@ -432,7 +492,7 @@ function valTypeToTS(attr, attrPath) {
         }
 
         case 'info_array':
-            return infoArrayToTS(attr);
+            return infoArrayToTS(attr, attrPath);
 
         case 'any':
             return 'any';
@@ -1080,7 +1140,16 @@ export function generateSchemaTypes(schema, outputPath) {
         ' * Do not edit by hand — run `npm run schema` to regenerate.',
         ' */',
         '',
-        "import type { Color, ColorScale, Datum, MarkerSymbol, TypedArray } from '../lib/common';",
+        'import type {',
+        '    CartesianSubplotId,',
+        '    Color,',
+        '    ColorScale,',
+        '    Datum,',
+        '    MarkerSymbol,',
+        '    TypedArray,',
+        '    XAxisName,',
+        '    YAxisName',
+        "} from '../lib/common';",
         ''
     ];
 
@@ -1265,7 +1334,21 @@ export function generateSchemaTypes(schema, outputPath) {
         }
     }
 
-    fs.writeFileSync(outputPath, chunks.join('\n'));
+    const output = chunks.join('\n');
+
+    // Backstop for the `/.../` regex convention. `enumValueToTS` already fails
+    // on an unmapped regex and names the attribute, but it only sees `values`
+    // entries. This catches a regex that reaches the output by another route.
+    const leakedRegexes = output.match(/'\/\^[^']*'/g);
+    if (leakedRegexes) {
+        throw new Error(
+            `Generated types contain regex string literals: ${[...new Set(leakedRegexes)].join(', ')}. ` +
+                `A schema regex reached the output as a literal type, which only accepts the pattern ` +
+                `text itself. Map it in REGEX_VALUE_TYPES.`
+        );
+    }
+
+    fs.writeFileSync(outputPath, output);
 
     const sharedCount = sharedList.length;
     const layoutCount = subplotGroups.size + arrayItems.size + 1; // +1 for Layout itself
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Handle regex enum values when generating schema types [[#8010](https://github.com/plotly/plotly.js/pull/8010)]