chore: fixes for 1st review

src/runtime/configs.ts

@@ -38,7 +38,11 @@ export const defaultFormats: Formats = {
   },
 };
 
-export const defaultOptions: ConfigureOptions = {
+export const defaultOptions: Omit<
+  ConfigureOptions,
+  'fallbackLocale' | 'initialLocale'
+> &
+  Record<'fallbackLocale' | 'initialLocale', null> = {
   fallbackLocale: null,
   initialLocale: null,
   loadingDelay: 200,

src/runtime/includes/formatters.ts

@@ -1,3 +1,4 @@
+import type { Formats } from 'intl-messageformat';
 import IntlMessageFormat from 'intl-messageformat';
 
 import type {
@@ -34,8 +35,8 @@ const getIntlFormatterOptions = (
 ): any => {
   const { formats } = getOptions();
 
-  if (type in formats && name in formats[type]) {
+  if (type in formats && name in (formats as Formats)[type]) {
-    return formats[type][name];
+    return (formats as Formats)[type][name];
   }
 
   throw new Error(`[svelte-i18n] Unknown "${name}" ${type} format.`);
@@ -105,7 +106,7 @@ export const getTimeFormatter: MemoizedDateTimeFormatterFactoryOptional = ({
 } = {}) => createTimeFormatter({ locale, ...args });
 
 export const getMessageFormatter = monadicMemoize(
-  (message: string, locale: string = getCurrentLocale()) =>
+  (message: string, locale: string = getCurrentLocale()!) =>
     new IntlMessageFormat(message, locale, getOptions().formats, {
       ignoreTag: getOptions().ignoreTag,
     }),

src/runtime/includes/loaderQueue.ts

@@ -62,13 +62,13 @@ function loadLocaleQueue(locale: string, localeQueue: MessagesLoader[]) {
 
 const activeFlushes: { [key: string]: Promise<void> } = {};
 
-export async function flush(locale: string): Promise<void> {
+export function flush(locale: string): Promise<void> {
   if (!hasLocaleQueue(locale)) {
     if (locale in activeFlushes) {
       return activeFlushes[locale];
     }
 
-    return;
+    return Promise.resolve();
   }
 
   // get queue of XX-YY and XX locales

src/runtime/stores/dictionary.ts

@@ -35,8 +35,8 @@ export function getMessageFromDictionary(locale: string, id: string) {
 }
 
 export function getClosestAvailableLocale(
-  refLocale: string,
+  refLocale: string | null | undefined,
-): string | null | undefined {
+): string | undefined {
   if (refLocale == null) return undefined;
 
   const relatedLocales = getPossibleLocales(refLocale);

src/runtime/stores/formatters.ts

@@ -47,7 +47,7 @@ const formatMessage: MessageFormatter = (id, options = {}) => {
         `[svelte-i18n] The message "${id}" was not found in "${getPossibleLocales(
           locale,
         ).join('", "')}".${
-          hasLocaleQueue(getCurrentLocale())
+          hasLocaleQueue(getCurrentLocale()!)
             ? `\n\nNote: there are at least one loader still registered to this locale that wasn't executed.`
             : ''
         }`,

src/runtime/stores/locale.ts

@@ -5,8 +5,8 @@ import { getOptions } from '../configs';
 import { getClosestAvailableLocale } from './dictionary';
 import { $isLoading } from './loading';
 
-let current: string;
+let current: string | null | undefined;
-const $locale = writable<string | null | undefined>(null);
+const internalLocale = writable<string | null | undefined>(null);
 
 function getSubLocales(refLocale: string) {
   return refLocale
@@ -32,18 +32,21 @@ export function getCurrentLocale() {
   return current;
 }
 
-$locale.subscribe((newLocale: string) => {
+internalLocale.subscribe((newLocale: string | null | undefined) => {
   current = newLocale;
 
-  if (typeof window !== 'undefined' && newLocale !== null) {
+  if (typeof window !== 'undefined' && newLocale != null) {
     document.documentElement.setAttribute('lang', newLocale);
   }
 });
 
-const localeSet = $locale.set;
+const set = (newLocale: string | null | undefined): void | Promise<void> => {
-
+  if (
-$locale.set = (newLocale: string): void | Promise<void> => {
+    ((getClosestAvailableLocale as unknown) as (
-  if (getClosestAvailableLocale(newLocale) && hasLocaleQueue(newLocale)) {
+      refLocale: string | null | undefined,
+    ) => refLocale is string)(newLocale) &&
+    hasLocaleQueue(newLocale)
+  ) {
     const { loadingDelay } = getOptions();
 
     let loadingTimer: number;
@@ -65,7 +68,7 @@ $locale.set = (newLocale: string): void | Promise<void> => {
 
     return flush(newLocale)
       .then(() => {
-        localeSet(newLocale);
+        internalLocale.set(newLocale);
       })
       .finally(() => {
         clearTimeout(loadingTimer);
@@ -73,12 +76,12 @@ $locale.set = (newLocale: string): void | Promise<void> => {
       });
   }
 
-  return localeSet(newLocale);
+  return internalLocale.set(newLocale);
 };
 
-// istanbul ignore next
+const $locale = {
-$locale.update = (
+  ...internalLocale,
-  fn: (value: string | null | undefined) => string | null | undefined,
+  set,
-) => localeSet(fn(current));
+};
 
 export { $locale };

src/runtime/types/index.ts

@@ -1,4 +1,4 @@
-import type { FormatXMLElementFn, Formats } from 'intl-messageformat';
+import type { Formats, FormatXMLElementFn } from 'intl-messageformat';
 
 export interface LocaleDictionary {
   [key: string]:
@@ -27,7 +27,7 @@ export type InterpolationValues =
 
 export interface MessageObject {
   id?: string;
-  locale?: string;
+  locale?: string | null;
   format?: string;
   default?: string;
   values?: InterpolationValues;
@@ -53,11 +53,11 @@ export type NumberFormatter = (
   options?: IntlFormatterOptions<Intl.NumberFormatOptions>,
 ) => string;
 
-export type JSONGetter = (id: string, locale?: string) => any;
+export type JSONGetter = (id: string, locale?: string | null) => any;
 
 type IntlFormatterOptions<T> = T & {
   format?: string;
-  locale?: string;
+  locale?: string | null;
 };
 
 export interface MemoizedIntlFormatter<T, U> {
@@ -73,14 +73,13 @@ export interface MessagesLoader {
 }
 
 export interface ConfigureOptions {
-  fallbackLocale: string | null | undefined;
+  fallbackLocale: string;
-  formats: Formats;
+  formats: Partial<Formats>;
-  initialLocale: string | null;
+  initialLocale: string;
   loadingDelay: number;
   warnOnMissingMessages: boolean;
   ignoreTag: boolean;
 }
 
 export type ConfigureOptionsInit = Pick<ConfigureOptions, 'fallbackLocale'> &
-  Partial<Record<'formats', Partial<ConfigureOptions['formats']>>> &
+  Partial<Omit<ConfigureOptions, 'fallbackLocale'>>;
-  Partial<Omit<ConfigureOptions, 'fallbackLocale' | 'formats'>>;

test/runtime/configs.test.ts

@@ -10,7 +10,7 @@ import {
 import { $locale } from '../../src/runtime/stores/locale';
 
 beforeEach(() => {
-  init(defaultOptions);
+  init(defaultOptions as any);
 });
 
 test('inits the fallback locale', () => {

test/runtime/includes/formatters.test.ts

@@ -10,7 +10,7 @@ import {
 const formatsJson = require('../../fixtures/formats.json');
 
 beforeEach(() => {
-  init({ fallbackLocale: undefined });
+  init({ fallbackLocale: undefined as any });
 });
 
 describe('number formatter', () => {

test/runtime/stores/locale.test.ts

@@ -11,7 +11,7 @@ import { register, isLoading } from '../../../src/runtime';
 import { hasLocaleQueue } from '../../../src/runtime/includes/loaderQueue';
 
 beforeEach(() => {
-  init({ fallbackLocale: undefined });
+  init({ fallbackLocale: undefined as any });
   $locale.set(undefined);
 });
 
@@ -90,7 +90,7 @@ test('if no initial locale is set, set the locale to the fallback', () => {
 test('if no initial locale was found, set to the fallback locale', () => {
   init({
     fallbackLocale: 'en',
-    initialLocale: null,
+    initialLocale: null as any,
   });
   expect(get($locale)).toBe('en');
   expect(getOptions().fallbackLocale).toBe('en');