diff --git a/lib/languages.js b/lib/languages.js
index 4924e79c8..2e839b098 100644
--- a/lib/languages.js
+++ b/lib/languages.js
@@ -1,22 +1,29 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 // All the languages supported by CodeQL
-exports.ALL_LANGUAGES = ['csharp', 'cpp', 'go', 'java', 'javascript', 'python'];
+var Language;
+(function (Language) {
+    Language["csharp"] = "csharp";
+    Language["cpp"] = "cpp";
+    Language["go"] = "go";
+    Language["java"] = "java";
+    Language["javascript"] = "javascript";
+    Language["python"] = "python";
+})(Language = exports.Language || (exports.Language = {}));
 // Additional names for languages
 const LANGUAGE_ALIASES = {
-    'c': 'cpp',
-    'c++': 'cpp',
-    'c#': 'csharp',
-    'typescript': 'javascript',
+    'c': Language.cpp,
+    'c++': Language.cpp,
+    'c#': Language.csharp,
+    'typescript': Language.javascript,
 };
 // Translate from user input or GitHub's API names for languages to CodeQL's names for languages
 function parseLanguage(language) {
     // Normalise to lower case
     language = language.toLowerCase();
     // See if it's an exact match
-    const parsedLanguage = exports.ALL_LANGUAGES.find(l => l === language);
-    if (parsedLanguage !== undefined) {
-        return parsedLanguage;
+    if (language in Language) {
+        return language;
     }
     // Check language aliases
     if (language in LANGUAGE_ALIASES) {
diff --git a/lib/languages.js.map b/lib/languages.js.map
index 47aa0e1c9..8cb6df90a 100644
--- a/lib/languages.js.map
+++ b/lib/languages.js.map
@@ -1 +1 @@
-{"version":3,"file":"languages.js","sourceRoot":"","sources":["../src/languages.ts"],"names":[],"mappings":";;AAAA,wCAAwC;AAC3B,QAAA,aAAa,GAAG,CAAC,QAAQ,EAAE,KAAK,EAAE,IAAI,EAAE,MAAM,EAAE,YAAY,EAAE,QAAQ,CAAU,CAAC;AAG9F,iCAAiC;AACjC,MAAM,gBAAgB,GAA+B;IACnD,GAAG,EAAE,KAAK;IACV,KAAK,EAAE,KAAK;IACZ,IAAI,EAAE,QAAQ;IACd,YAAY,EAAE,YAAY;CAC3B,CAAC;AAEF,gGAAgG;AAChG,SAAgB,aAAa,CAAC,QAAgB;IAC5C,0BAA0B;IAC1B,QAAQ,GAAG,QAAQ,CAAC,WAAW,EAAE,CAAC;IAElC,6BAA6B;IAC7B,MAAM,cAAc,GAAG,qBAAa,CAAC,IAAI,CAAC,CAAC,CAAC,EAAE,CAAC,CAAC,KAAK,QAAQ,CAAC,CAAC;IAC/D,IAAI,cAAc,KAAK,SAAS,EAAE;QAChC,OAAO,cAAc,CAAC;KACvB;IAED,yBAAyB;IACzB,IAAI,QAAQ,IAAI,gBAAgB,EAAE;QAChC,OAAO,gBAAgB,CAAC,QAAQ,CAAC,CAAC;KACnC;IAED,OAAO,SAAS,CAAC;AACnB,CAAC;AAhBD,sCAgBC;AAGD,SAAgB,gBAAgB,CAAC,QAAkB;IACjD,OAAO,CAAC,KAAK,EAAE,MAAM,EAAE,QAAQ,CAAC,CAAC,QAAQ,CAAC,QAAQ,CAAC,CAAC;AACtD,CAAC;AAFD,4CAEC;AAED,SAAgB,iBAAiB,CAAC,QAAkB;IAClD,OAAO,CAAC,gBAAgB,CAAC,QAAQ,CAAC,CAAC;AACrC,CAAC;AAFD,8CAEC"}
\ No newline at end of file
+{"version":3,"file":"languages.js","sourceRoot":"","sources":["../src/languages.ts"],"names":[],"mappings":";;AAAA,wCAAwC;AACxC,IAAY,QAOX;AAPD,WAAY,QAAQ;IAClB,6BAAiB,CAAA;IACjB,uBAAW,CAAA;IACX,qBAAS,CAAA;IACT,yBAAa,CAAA;IACb,qCAAyB,CAAA;IACzB,6BAAiB,CAAA;AACnB,CAAC,EAPW,QAAQ,GAAR,gBAAQ,KAAR,gBAAQ,QAOnB;AAED,iCAAiC;AACjC,MAAM,gBAAgB,GAA+B;IACnD,GAAG,EAAE,QAAQ,CAAC,GAAG;IACjB,KAAK,EAAE,QAAQ,CAAC,GAAG;IACnB,IAAI,EAAE,QAAQ,CAAC,MAAM;IACrB,YAAY,EAAE,QAAQ,CAAC,UAAU;CAClC,CAAC;AAEF,gGAAgG;AAChG,SAAgB,aAAa,CAAC,QAAgB;IAC5C,0BAA0B;IAC1B,QAAQ,GAAG,QAAQ,CAAC,WAAW,EAAE,CAAC;IAElC,6BAA6B;IAC7B,IAAI,QAAQ,IAAI,QAAQ,EAAE;QACxB,OAAO,QAAoB,CAAC;KAC7B;IAED,yBAAyB;IACzB,IAAI,QAAQ,IAAI,gBAAgB,EAAE;QAChC,OAAO,gBAAgB,CAAC,QAAQ,CAAC,CAAC;KACnC;IAED,OAAO,SAAS,CAAC;AACnB,CAAC;AAfD,sCAeC;AAGD,SAAgB,gBAAgB,CAAC,QAAkB;IACjD,OAAO,CAAC,KAAK,EAAE,MAAM,EAAE,QAAQ,CAAC,CAAC,QAAQ,CAAC,QAAQ,CAAC,CAAC;AACtD,CAAC;AAFD,4CAEC;AAED,SAAgB,iBAAiB,CAAC,QAAkB;IAClD,OAAO,CAAC,gBAAgB,CAAC,QAAQ,CAAC,CAAC;AACrC,CAAC;AAFD,8CAEC"}
\ No newline at end of file
diff --git a/src/languages.ts b/src/languages.ts
index 3a2ecdb16..40c1de7ab 100644
--- a/src/languages.ts
+++ b/src/languages.ts
@@ -1,13 +1,19 @@
 // All the languages supported by CodeQL
-export const ALL_LANGUAGES = ['csharp', 'cpp', 'go', 'java', 'javascript', 'python'] as const;
-export type Language = (typeof ALL_LANGUAGES)[number];
+export enum Language {
+  csharp = 'csharp',
+  cpp = 'cpp',
+  go = 'go',
+  java = 'java',
+  javascript = 'javascript',
+  python = 'python',
+}
 
 // Additional names for languages
 const LANGUAGE_ALIASES: {[lang: string]: Language} = {
-  'c': 'cpp',
-  'c++': 'cpp',
-  'c#': 'csharp',
-  'typescript': 'javascript',
+  'c': Language.cpp,
+  'c++': Language.cpp,
+  'c#': Language.csharp,
+  'typescript': Language.javascript,
 };
 
 // Translate from user input or GitHub's API names for languages to CodeQL's names for languages
@@ -16,9 +22,8 @@ export function parseLanguage(language: string): Language | undefined {
   language = language.toLowerCase();
 
   // See if it's an exact match
-  const parsedLanguage = ALL_LANGUAGES.find(l => l === language);
-  if (parsedLanguage !== undefined) {
-    return parsedLanguage;
+  if (language in Language) {
+    return language as Language;
   }
 
   // Check language aliases