Fix remaining type/lint errors and test failures

.eslintrc.json

@@ -63,6 +63,7 @@
             }
         ],
         "import/order": "warn",
+        "import/prefer-default-export": "off",
         "no-param-reassign": "warn",
         "no-restricted-syntax": [
             "warn",
@@ -93,7 +94,13 @@
         {
             "files": ["./**/*.ts"],
             "rules": {
-                "@typescript-eslint/no-unused-expressions": "off",
+                "no-useless-constructor": "off",
+                "@typescript-eslint/no-useless-constructor": "error",
+                "no-unused-vars": "off",
+                "@typescript-eslint/no-unused-vars": "error",
+                "no-empty-function": "off",
+                "@typescript-eslint/no-empty-function": "error",
+
                 "import/extensions": [
                     "error",
                     "ignorePackages",
@@ -107,6 +114,20 @@
             }
         },
 
+        {
+            "files": ["./test/**/*.ts"],
+            "rules": {
+                "@typescript-eslint/no-unused-expressions": "off"
+            }
+        },
+
+        {
+            "files": ["./**/*.d.ts"],
+            "rules": {
+                "no-unused-vars": "off"
+            }
+        },
+
         {
             "files": ["./test/**/*.ts"],
             "plugins": ["vitest"],

package.json

@@ -20,14 +20,15 @@
     "contributors": [],
     "scripts": {
         "start": "node app.js",
-        "eslint-check": "eslint app.js src/**/*.js vite.config.ts test/**/*.ts",
-        "eslint-fix": "eslint app.js src/**/*.js vite.config.ts test/**/*.ts --fix",
+        "eslint-check": "eslint app.ts src/**/*.ts vite.config.ts test/**/*.ts",
+        "eslint-fix": "eslint app.ts src/**/*.ts vite.config.ts test/**/*.ts --fix",
         "prettier-fix": "prettier --write .",
         "test": "vitest run --coverage && npm run prettier-fix && npm run eslint-fix && tsc && node update-readme-with-shield-badge.js",
         "test:watch": "vitest",
         "build-docs": "rimraf docs && ./node_modules/.bin/jsdoc -c jsdoc.config.js",
         "develop": "DEBUG=api,transformer,markdown,language node app.js & http-server test/forms -p 8081",
-        "tsc": "tsc"
+        "develop": "DEBUG=api,transformer,markdown,language node app.ts & http-server test/forms -p 8081",
+        "tsc": "tsc --project . && tsc --project ./test"
     },
     "repository": {
         "type": "git",

src/language.ts

@@ -3,7 +3,10 @@ import stringDirection from 'string-direction';
 
 import type { Tag, Subtag } from 'language-tags';
 
-class Language {
+/**
+ * @package
+ */
+export class Language {
     /**
      * Included for backwards compatibility, prefer:
      *
@@ -40,7 +43,6 @@ class Language {
 }
 
 export type {
-    Language,
     /**
      * Exported for backwards compatibility, prefer:
      *
@@ -68,25 +70,25 @@ export const parseLanguage = (
 
     const parts = sourceLanguage.match(/^([^(]+)\((.*)\)\s*$/);
 
-    if (parts && parts.length > 2) {
-        description = parts[1].trim();
-        tag = parts[2].trim();
-    } else {
-        // First check whether `sourceLanguage` is a known IANA subtag like 'en' or 'en-GB'
-        const languageFromTag = getLanguageFromSubtag(
-            sourceLanguage.split('-')[0]
+    if (parts && parts.length >= 2) {
+        return new Language(
+            sourceLanguage,
+            parts[1].trim(),
+            parts[2].trim(),
+            directionality
         );
+    }
+    // First check whether `sourceLanguage` is a known IANA subtag like 'en' or 'en-GB'
+    const languageFromTag = getLanguageFromSubtag(sourceLanguage.split('-')[0]);
 
-        if (languageFromTag == null) {
-            const { subtag } =
-                getLanguageFromDescription(description)?.data ?? {};
+    if (languageFromTag == null) {
+        const language = getLanguageFromDescription(description);
 
-            if (subtag != null) {
-                tag = subtag;
-            }
-        } else {
-            description = languageFromTag.descriptions()[0];
+        if (typeof language === 'object' && language.data.subtag != null) {
+            tag = language.data.subtag;
         }
+    } else {
+        description = languageFromTag.descriptions()[0];
     }
 
     return new Language(sourceLanguage, description, tag, directionality);
@@ -96,13 +98,15 @@ export const parseLanguage = (
  * Performs IANA search to find language object with provided description.
  */
 const getLanguageFromDescription = (description: string) =>
-    tags.search(description).find(isLanguage);
+    description.trim() === ''
+        ? ''
+        : tags.search(description).find(isLanguage) ?? '';
 
 /**
  * Performs IANA search to find language object with provided subtag.
  */
 const getLanguageFromSubtag = (subtag: string) =>
-    tags.subtags(subtag).find(isLanguage) ?? null;
+    subtag.trim() === '' ? null : tags.subtags(subtag).find(isLanguage) ?? null;
 
 const isLanguage = (object: Tag | Subtag) => object.data.type === 'language';
 

test/bad-external.spec.ts

@@ -31,7 +31,7 @@ describe('for incompatible forms that require preprocessing', () => {
                     return;
                 }
 
-                const query = q.value();
+                const query = q.value()!;
                 const ref = r.value();
 
                 /**
@@ -85,7 +85,7 @@ describe('for incompatible forms that require preprocessing', () => {
                     if (name !== 'query') {
                         const value = attr.value();
 
-                        select1.attr(name, value);
+                        select1.attr(name, value!);
                     }
                 });