Add Flow declarations

CHANGELOG.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+  - Add local Flow declarations (shipped with the package).
+    We don't necessarily want to contribute the fork definitions to flow-typed.
 
 ## [1.0.0] - 2024-09-06
 ### Changed

index.js.flow

@@ -0,0 +1,71 @@
+// @flow
+
+export type Options = {
+  locale?: string,
+  fallbackLocale?: string,
+  separator?: string,
+  fallback?: string,
+  scope?: string | string[],
+  interpolate?: boolean,
+  format?: 'default' | string,
+  type?: 'datetime' | string,
+  // @TODO: check if other types than number are really allowed.
+  count?: number | string | null,
+  ...
+};
+
+export type NotFoundHandler = (evt: {
+  ...CustomEvent,
+  detail: { locale: string, key: string, fallback: string, scope: string },
+  ...
+}) => void;
+
+export type LocaleChangeHandler = (evt: {
+  ...CustomEvent,
+  detail: {
+    locale: string,
+    previous: string,
+  },
+  ...
+}) => void;
+
+export type ErrorHandler = (evt: {
+  ...CustomEvent,
+  detail: {
+    error: Error,
+    entry: string,
+    values: Options,
+  },
+  ...
+}) => void;
+
+declare function translate(key: string | string[], options?: Options): string;
+
+declare class Counterpart {
+  constructor(): this;
+
+  translate: typeof translate;
+  localize(date: Date, options: { ... }): string;
+  setSeparator(value: string): string;
+  setMissingEntryGenerator(callback: (value: string) => void): void;
+  getLocale(): string;
+  setLocale(value: string): string;
+  setFallbackLocale(value: string | string[]): void;
+  registerTranslations(locale: string, data: { ... }): void;
+  registerInterpolations(data: { ... }): void;
+  setKeyTransformer(
+    callback: (value: string, options: { ... }) => string,
+  ): string;
+  onLocaleChange(callback: LocaleChangeHandler): void;
+  offLocaleChange(callback: LocaleChangeHandler): void;
+  onTranslationNotFound(callback: NotFoundHandler): void;
+  offTranslationNotFound(callback: NotFoundHandler): void;
+  onError(callback: ErrorHandler): void;
+  offError(callback: ErrorHandler): void;
+}
+
+declare module.exports: {
+  Instance: Class<Counterpart>,
+  Translator: Class<Counterpart>,
+} & Counterpart &
+  typeof translate;

package.json

@@ -38,6 +38,7 @@
   "files": [
     "locales",
     "index.js",
+    "index.js.flow",
     "strftime.js",
     "README.md",
     "LICENSE"