refactor: enable strictNullChecks in conf package (#2334)

Author: vonovak

packages/cli/src/api/catalog/getFallbackListForLocale.ts

@@ -11,8 +11,11 @@ export function getFallbackListForLocale(
     Array.isArray(mapping) ? fL.push(...mapping) : fL.push(mapping)
   }
 
-  if (fallbackLocales?.default && locale !== fallbackLocales?.default) {
-    fL.push(fallbackLocales?.default)
+  if (
+    typeof fallbackLocales?.default === "string" &&
+    locale !== fallbackLocales?.default
+  ) {
+    fL.push(fallbackLocales.default)
   }
 
   return fL

packages/conf/src/getConfig.ts

@@ -6,8 +6,8 @@ import { makeConfig } from "./makeConfig"
 import { createJiti } from "jiti"
 import pico from "picocolors"
 
-function configExists(path: string) {
-  return path && fs.existsSync(path)
+function configExists(path?: string): path is string {
+  return !!path && fs.existsSync(path)
 }
 
 function JitiLoader(): LoaderSync {

packages/conf/src/migrations/setCldrParentLocales.ts

@@ -10,7 +10,7 @@ export function setCldrParentLocales(
     } as unknown as LinguiConfigNormalized
   }
 
-  if (!config.fallbackLocales.default) {
+  if (!config.fallbackLocales?.default) {
     config.locales.forEach((locale) => {
       const fl = getCldrParentLocale(locale.toLowerCase())
       if (fl && !(config.fallbackLocales as FallbackLocales)[locale]) {

packages/conf/src/types.ts

@@ -106,10 +106,11 @@ export type CatalogConfig = {
   exclude?: string[]
 }
 
-type LocaleObject = {
-  [locale: string]: string[] | string
-  default?: string
-}
+type LocaleObject =
+  | Record<string, string[] | string>
+  | (Record<string, string[] | string> & {
+      default: string
+    })
 
 export type FallbackLocales = LocaleObject
 
@@ -257,7 +258,7 @@ export type LinguiConfig = {
    *
    * Note that using <rootDir> as a string token in any other path-based config settings will refer back to this value.
    *
-   * @defaul: The root of the directory containing your Lingui configuration file or the package.json.
+   * @default: The root of the directory containing your Lingui configuration file or the package.json.
    */
   rootDir?: string
   /**

packages/conf/src/utils/replaceRootDir.ts

@@ -2,8 +2,11 @@ import { LinguiConfig } from "../types"
 
 export function replaceRootDir<T extends Partial<LinguiConfig>>(
   config: T,
-  rootDir: string
+  rootDir: string | undefined
 ): T {
+  if (!rootDir) {
+    return config
+  }
   return (function replaceDeep(value: any, rootDir: string): any {
     const replace = (s: string) => s.replace("<rootDir>", rootDir)
 

packages/conf/tsconfig.json

@@ -10,7 +10,6 @@
     "resolveJsonModule": true,
     "skipLibCheck": true,
     "strict": true,
-    "strictNullChecks": false
   },
   "files": [
     "./src/index.ts"