diff --git a/src/highlight.js b/src/highlight.js
index e525d94354..e0406d91eb 100644
--- a/src/highlight.js
+++ b/src/highlight.js
@@ -107,7 +107,7 @@ const HLJS = function(hljs) {
    * @property {boolean} illegal - indicates whether any illegal matches were found
   */
   function highlight(languageName, code, ignoreIllegals, continuation) {
-    /** @type {{ code: string, language: string, result?: any }} */
+    /** @type {BeforeHighlightContext} */
     const context = {
       code,
       language: languageName
diff --git a/src/lib/logger.js b/src/lib/logger.js
index e5ccce4493..d102f74aea 100644
--- a/src/lib/logger.js
+++ b/src/lib/logger.js
@@ -14,9 +14,10 @@ export const error = (message) => {
 
 /**
  * @param {string} message
+ * @param {any} args
  */
-export const warn = (message) => {
-  console.log(`WARN: ${message}`);
+export const warn = (message, ...args) => {
+  console.log(`WARN: ${message}`, ...args);
 };
 
 /**
diff --git a/types/index.d.ts b/types/index.d.ts
index c66773faae..fa5b06f9bf 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -1,3 +1,5 @@
+/* eslint-disable no-unused-vars */
+/* eslint-disable no-use-before-define */
 // For TS consumers who use Node and don't have dom in their tsconfig lib, import the necessary types here.
 /// <reference lib="dom" />
 
@@ -77,6 +79,7 @@ interface HighlightResult {
     errorRaised? : Error
     // * for auto-highlight
     second_best? : Omit<HighlightResult, 'second_best'>
+    code?: string
 }
 interface AutoHighlightResult extends HighlightResult {}
 
@@ -86,14 +89,17 @@ interface illegalData {
     mode: CompiledMode
 }
 
-type PluginEvent =
-    'before:highlight'
-    | 'after:highlight'
-    | 'before:highlightBlock'
-    | 'after:highlightBlock'
-
+type BeforeHighlightContext = {
+  code: string,
+  language: string,
+  result?: HighlightResult
+}
+type PluginEvent = keyof HLJSPlugin;
 type HLJSPlugin = {
-    [K in PluginEvent]? : any
+    'after:highlight'?: (result: HighlightResult) => void,
+    'before:highlight'?: (context: BeforeHighlightContext) => void,
+    'after:highlightBlock'?: (data: { result: HighlightResult}) => void,
+    'before:highlightBlock'?: (data: { block: Element, language: string}) => void,
 }
 
 interface EmitterConstructor {
@@ -162,6 +168,7 @@ interface LanguageDetail {
     exports?: any,
     classNameAliases?: Record<string, string>
     compilerExtensions?: CompilerExt[]
+    supersetOf?: string
 }
 
 type Language = LanguageDetail & Partial<Mode>