2 files changed, 37 insertions, 19 deletions

diff --git a/src/data/composite/wiki-data/inputThingClass.js b/src/data/composite/wiki-data/inputThingClass.js
index d70480e6..5f2ca5a6 100644
--- a/src/data/composite/wiki-data/inputThingClass.js
+++ b/src/data/composite/wiki-data/inputThingClass.js
@@ -3,7 +3,7 @@
 // referencing Thing class values defined outside of the #composite folder.
 
 import {input} from '#composite';
-import {isType} from '#validators';
+import {isFunction} from '#validators';
 
 // TODO: Kludge.
 import Thing from '../../things/thing.js';
@@ -11,7 +11,7 @@ import Thing from '../../things/thing.js';
 export default function inputThingClass() {
   return input.staticValue({
     validate(thingClass) {
-      isType(thingClass, 'function');
+      isFunction(thingClass);
 
       if (!Object.hasOwn(thingClass, Thing.referenceType)) {
         throw new TypeError(`Expected a Thing constructor, missing Thing.referenceType`);
diff --git a/src/data/things/validators.js b/src/data/things/validators.js
index 94c73b2a..027aa195 100644
--- a/src/data/things/validators.js
+++ b/src/data/things/validators.js
@@ -32,21 +32,38 @@ export function a(noun) {
   return /[aeiou]/.test(noun[0]) ? `an ${noun}` : `a ${noun}`;
 }
 
-export function isType(value, type) {
-  if (typeof value !== type)
-    throw new TypeError(`Expected ${a(type)}, got ${typeAppearance(value)}`);
+export function validateType(type) {
+  const fn = value => {
+    if (typeof value !== type)
+      throw new TypeError(`Expected ${a(type)}, got ${typeAppearance(value)}`);
 
-  return true;
-}
+    return true;
+  };
 
-export function isBoolean(value) {
-  return isType(value, 'boolean');
-}
+  setValidatorCreatorMeta(fn, validateType, {type});
 
-export function isNumber(value) {
-  return isType(value, 'number');
+  return fn;
 }
 
+export const isBoolean =
+  validateType('boolean');
+
+export const isFunction =
+  validateType('function');
+
+export const isNumber =
+  validateType('number');
+
+export const isString =
+  validateType('string');
+
+export const isSymbol =
+  validateType('symbol');
+
+// Use isObject instead, which disallows null.
+export const isTypeofObject =
+  validateType('object');
+
 export function isPositive(number) {
   isNumber(number);
 
@@ -101,10 +118,6 @@ export function isWholeNumber(number) {
   return true;
 }
 
-export function isString(value) {
-  return isType(value, 'string');
-}
-
 export function isStringNonEmpty(value) {
   isString(value);
 
@@ -142,12 +155,13 @@ export function isDate(value) {
 }
 
 export function isObject(value) {
-  isType(value, 'object');
+  isTypeofObject(value);
 
   // Note: Please remember that null is always a valid value for properties
   // held by a CacheableObject. This assertion is exclusively for use in other
   // contexts.
-  if (value === null) throw new TypeError(`Expected an object, got null`);
+  if (value === null)
+    throw new TypeError(`Expected an object, got null`);
 
   return true;
 }
@@ -245,7 +259,11 @@ export function sparseArrayOf(itemValidator) {
 }
 
 export function validateInstanceOf(constructor) {
-  return (object) => isInstance(object, constructor);
+  const fn = (object) => isInstance(object, constructor);
+
+  setValidatorCreatorMeta(fn, validateInstanceOf, {constructor});
+
+  return fn;
 }
 
 // Wiki data (primitives & non-primitives)