fix: expose language detection

src/common/languages.ts

@@ -1,12 +1,14 @@
-type ListItem = {
+import path from 'node:path';
+
+export type LangListItem = {
   extensions: string[];
   group: string | null;
   name: string;
   type: 'data' | 'markup' | 'programming' | 'prose';
 };
 
 // Source: https://github.com/github/linguist/blob/5a0c74277548122267d84283910abd5e0b89380e/lib/linguist/languages.yml#L1528
-export const rawList: ListItem[] = [
+export const rawList: LangListItem[] = [
   {
     extensions: ['.bsl', '.os'],
     group: null,
@@ -4428,3 +4430,28 @@ export const rawList: ListItem[] = [
 
 export const languages = rawList.filter((l) => l.type === 'programming');
 export const others = rawList.filter((l) => l.type !== 'programming');
+
+/**
+ * Detect language of a file at this level.
+ */
+export function detectLang(filename: string): LangListItem | null {
+  const ext = path.extname(filename);
+
+  for (const lang of languages) {
+    if (!lang.extensions.includes(ext)) {
+      continue;
+    }
+
+    return lang;
+  }
+
+  for (const lang of others) {
+    if (!lang.extensions.includes(ext)) {
+      continue;
+    }
+
+    return lang;
+  }
+
+  return null;
+}

src/index.ts

@@ -1,5 +1,10 @@
 /* eslint-disable import/extensions */
 import { analyser } from './analyser/index.js';
+import {
+  LangListItem,
+  detectLang,
+  rawList as languageList,
+} from './common/languages.js';
 import { listIndexed, listTech } from './common/techs.generated.js';
 import {
   rawList,
@@ -55,6 +60,7 @@ export {
   TechItem,
   TechMatcher,
   TechType,
+  LangListItem,
 };
 
 export {
@@ -82,3 +88,8 @@ export const tech = {
   list: listTech,
   keys: registeredTech,
 };
+
+export const lang = {
+  detect: detectLang,
+  list: languageList,
+};

src/payload/index.ts

@@ -1,6 +1,6 @@
 import path from 'node:path';
 
-import { languages, others } from '../common/languages.js';
+import { detectLang } from '../common/languages.js';
 import { nid } from '../common/nid.js';
 import { rulesComponents, rulesTechs } from '../loader.js';
 import type { BaseProvider } from '../provider/base.js';
@@ -231,24 +231,9 @@ export class Payload implements Analyser {
    * Detect language of a file at this level.
    */
   detectLang(filename: string) {
-    const ext = path.extname(filename);
-
-    for (const lang of languages) {
-      if (!lang.extensions.includes(ext)) {
-        continue;
-      }
-
-      this.addLang(lang.group || lang.name);
-      return;
-    }
-
-    for (const lang of others) {
-      if (!lang.extensions.includes(ext)) {
-        continue;
-      }
-
+    const lang = detectLang(filename);
+    if (lang) {
       this.addLang(lang.group || lang.name);
-      return;
     }
   }