refactor: add ciaplu for pattern matching in language detection and MIME type resolution

Author: Fabio286

package-lock.json

@@ -131,6 +131,7 @@
     "babel-loader": "~8.2.3",
     "better-sqlite3": "~10.0.0",
     "chalk": "~4.1.2",
+    "ciaplu": "^2.2.0",
     "cpu-features": "^0.0.10",
     "cross-env": "~7.0.2",
     "css-loader": "~6.5.0",

package.json

@@ -1,3 +1,5 @@
+import { match } from 'ciaplu';
+
 function isJSON (str: string) {
    try {
       if (!['{', '['].includes(str.trim()[0]))
@@ -176,17 +178,13 @@ function isMD (str: string) {
 }
 
 export function langDetector (str: string) {
-   if (!str || !str.trim().length)
-      return 'text';
-   if (isJSON(str))
-      return 'json';
-   if (isHTML(str))
-      return 'html';
-   if (isSVG(str))
-      return 'svg';
-   if (isXML(str))
-      return 'xml';
-   if (isMD(str))
-      return 'markdown';
-   return 'text';
+   return match(str)
+      .when(() => !str || !str.trim().length, () => 'text')
+      .when(isJSON, () => 'json')
+      .when(isHTML, () => 'html')
+      .when(isSVG, () => 'svg')
+      .when(isXML, () => 'xml')
+      .when(isMD, () => 'markdown')
+      .otherwise(() => 'text')
+      .return();
 }

src/common/libs/langDetector.ts

@@ -1,45 +1,25 @@
+import { match } from 'ciaplu';
+
 export function mimeFromHex (hex: string) {
-   switch (hex.substring(0, 4)) { // 2 bytes
-      case '424D':
-         return { ext: 'bmp', mime: 'image/bmp' };
-      case '1F8B':
-         return { ext: 'tar.gz', mime: 'application/gzip' };
-      case '0B77':
-         return { ext: 'ac3', mime: 'audio/vnd.dolby.dd-raw' };
-      case '7801':
-         return { ext: 'dmg', mime: 'application/x-apple-diskimage' };
-      case '4D5A':
-         return { ext: 'exe', mime: 'application/x-msdownload' };
-      case '1FA0':
-      case '1F9D':
-         return { ext: 'Z', mime: 'application/x-compress' };
-      default:
-         switch (hex.substring(0, 6)) { // 3 bytes
-            case 'FFD8FF':
-               return { ext: 'jpg', mime: 'image/jpeg' };
-            case '4949BC':
-               return { ext: 'jxr', mime: 'image/vnd.ms-photo' };
-            case '425A68':
-               return { ext: 'bz2', mime: 'application/x-bzip2' };
-            default:
-               switch (hex) { // 4 bites
-                  case '89504E47':
-                     return { ext: 'png', mime: 'image/png' };
-                  case '47494638':
-                     return { ext: 'gif', mime: 'image/gif' };
-                  case '25504446':
-                     return { ext: 'pdf', mime: 'application/pdf' };
-                  case '504B0304':
-                     return { ext: 'zip', mime: 'application/zip' };
-                  case '425047FB':
-                     return { ext: 'bpg', mime: 'image/bpg' };
-                  case '4D4D002A':
-                     return { ext: 'tif', mime: 'image/tiff' };
-                  case '00000100':
-                     return { ext: 'ico', mime: 'image/x-icon' };
-                  default:
-                     return { ext: '', mime: 'unknown ' + hex };
-               }
-         }
-   }
+   return match(hex.substring(0, 4)) // 2 bytes
+      .with('424D', () => ({ ext: 'bmp', mime: 'image/bmp' }))
+      .with('1F8B', () => ({ ext: 'tar.gz', mime: 'application/gzip' }))
+      .with('0B77', () => ({ ext: 'ac3', mime: 'audio/vnd.dolby.dd-raw' }))
+      .with('7801', () => ({ ext: 'dmg', mime: 'application/x-apple-diskimage' }))
+      .with('4D5A', () => ({ ext: 'exe', mime: 'application/x-msdownload' }))
+      .when((val) => ['1FA0', '1F9D'].includes(val), () => ({ ext: 'Z', mime: 'application/x-compress' }))
+      .extracting(() => hex.substring(0, 6)) // 3 bytes
+      .with('FFD8FF', () => ({ ext: 'jpg', mime: 'image/jpeg' }))
+      .with('4949BC', () => ({ ext: 'jxr', mime: 'image/vnd.ms-photo' }))
+      .with('425A68', () => ({ ext: 'bz2', mime: 'application/x-bzip2' }))
+      .extracting(() => hex) // 4 bytes
+      .with('89504E47', () => ({ ext: 'png', mime: 'image/png' }))
+      .with('47494638', () => ({ ext: 'gif', mime: 'image/gif' }))
+      .with('25504446', () => ({ ext: 'pdf', mime: 'application/pdf' }))
+      .with('504B0304', () => ({ ext: 'zip', mime: 'application/zip' }))
+      .with('425047FB', () => ({ ext: 'bpg', mime: 'image/bpg' }))
+      .with('4D4D002A', () => ({ ext: 'tif', mime: 'image/tiff' }))
+      .with('00000100', () => ({ ext: 'ico', mime: 'image/x-icon' }))
+      .otherwise(() => ({ ext: '', mime: 'unknown ' + hex }))
+      .return();
 }