refactor: assertLocaleData returns a value

Author: ST-DDT

src/internal/assert-locale-data.ts

@@ -0,0 +1,32 @@
+import { FakerError } from '../errors/faker-error';
+
+/**
+ * Checks that the value is not null or undefined and throws an error if it is.
+ *
+ * @param value The value to check.
+ * @param path The path to the locale data.
+ *
+ * @returns The value if it's not null or undefined.
+ *
+ * @throws {FakerError} If the value is null or undefined.
+ */
+export function assertLocaleData<T>(
+  value: T,
+  ...path: string[]
+): NonNullable<T> {
+  if (value === null) {
+    throw new FakerError(
+      `The locale data for '${path.join('.')}' aren't applicable to this locale.
+  If you think this is a bug, please report it at: https://github.com/faker-js/faker`
+    );
+  } else if (value === undefined) {
+    throw new FakerError(
+      `The locale data for '${path.join('.')}' are missing in this locale.
+  If this is a custom Faker instance, please make sure all required locales are used e.g. '[de_AT, de, en, base]'.
+  Please contribute the missing data to the project or use a locale/Faker instance that has these data.
+  For more information see https://fakerjs.dev/guide/localization.html`
+    );
+  }
+
+  return value;
+}

src/internal/locale-proxy.ts

@@ -1,5 +1,6 @@
 import type { LocaleDefinition } from '../definitions';
 import { FakerError } from '../errors/faker-error';
+import { assertLocaleData } from './assert-locale-data';
 
 /**
  * A proxy for LocaleDefinition that marks all properties as required and throws an error when an entry is accessed that is not defined.
@@ -54,31 +55,6 @@ export function createLocaleProxy(locale: LocaleDefinition): LocaleProxy {
   }) as LocaleProxy;
 }
 
-/**
- * Checks that the value is not null or undefined and throws an error if it is.
- *
- * @param value The value to check.
- * @param path The path to the locale data.
- */
-export function assertLocaleData<T>(
-  value: T,
-  ...path: string[]
-): asserts value is NonNullable<T> {
-  if (value === null) {
-    throw new FakerError(
-      `The locale data for '${path.join('.')}' aren't applicable to this locale.
-  If you think this is a bug, please report it at: https://github.com/faker-js/faker`
-    );
-  } else if (value === undefined) {
-    throw new FakerError(
-      `The locale data for '${path.join('.')}' are missing in this locale.
-  If this is a custom Faker instance, please make sure all required locales are used e.g. '[de_AT, de, en, base]'.
-  Please contribute the missing data to the project or use a locale/Faker instance that has these data.
-  For more information see https://fakerjs.dev/guide/localization.html`
-    );
-  }
-}
-
 /**
  * Creates a proxy for a category that throws an error when accessing an undefined property.
  *
@@ -106,8 +82,7 @@ function createCategoryProxy<
         return value;
       }
 
-      assertLocaleData(value, categoryName, entryName.toString());
-      return value;
+      return assertLocaleData(value, categoryName, entryName.toString());
     },
 
     set: throwReadOnlyError,

src/modules/date/index.ts

@@ -1,8 +1,8 @@
 import type { DateEntryDefinition } from '../../definitions';
 import { FakerError } from '../../errors/faker-error';
 import type { Faker } from '../../faker';
+import { assertLocaleData } from '../../internal/assert-locale-data';
 import { toDate } from '../../internal/date';
-import { assertLocaleData } from '../../internal/locale-proxy';
 import { SimpleModuleBase } from '../../internal/module-base';
 
 /**
@@ -657,9 +657,9 @@ export class DateModule extends SimpleDateModule {
       type = useContext ? 'wide_context' : 'wide';
     }
 
-    const values = source[type];
-    assertLocaleData(values, 'date.month', type);
-    return this.faker.helpers.arrayElement(values);
+    return this.faker.helpers.arrayElement(
+      assertLocaleData(source[type], 'date.month', type)
+    );
   }
 
   /**
@@ -709,9 +709,9 @@ export class DateModule extends SimpleDateModule {
       type = useContext ? 'wide_context' : 'wide';
     }
 
-    const values = source[type];
-    assertLocaleData(values, 'date.weekday', type);
-    return this.faker.helpers.arrayElement(values);
+    return this.faker.helpers.arrayElement(
+      assertLocaleData(source[type], 'date.weekday', type)
+    );
   }
 
   /**