diff --git a/src/Instance.ts b/src/Instance.ts
index 90193017..6788d3dd 100644
--- a/src/Instance.ts
+++ b/src/Instance.ts
@@ -259,28 +259,30 @@ export class Marked {
   #convertRendererFunction(func: GenericRendererFunction, prop: string, renderer: _Renderer) {
     switch (prop) {
       case 'heading':
-        return function(token: Tokens.Heading) {
+        return function(this: _Renderer, token: Tokens.Heading) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(
+          return func.call(
+            this,
             renderer.parser.parseInline(token.tokens),
             token.depth,
             unescape(renderer.parser.parseInline(token.tokens, renderer.parser.textRenderer))
           );
         };
       case 'code':
-        return function(token: Tokens.Code) {
+        return function(this: _Renderer, token: Tokens.Code) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(
+          return func.call(
+            this,
             token.text,
             token.lang,
             !!token.escaped
@@ -328,7 +330,7 @@ export class Marked {
             body += this.tablerow({ text: cell });
           }
 
-          return func(header, body);
+          return func.call(this, header, body);
         };
       case 'blockquote':
         return function(this: _Renderer, token: Tokens.Blockquote) {
@@ -339,7 +341,7 @@ export class Marked {
           }
 
           const body = this.parser.parse(token.tokens);
-          return func(body);
+          return func.call(this, body);
         };
       case 'list':
         return function(this: _Renderer, token: Tokens.List) {
@@ -391,17 +393,17 @@ export class Marked {
             });
           }
 
-          return func(body, ordered, start);
+          return func.call(this, body, ordered, start);
         };
       case 'html':
-        return function(token: Tokens.HTML) {
+        return function(this: _Renderer, token: Tokens.HTML) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(token.text, token.block);
+          return func.call(this, token.text, token.block);
         };
       case 'paragraph':
         return function(this: _Renderer, token: Tokens.Paragraph) {
@@ -411,17 +413,17 @@ export class Marked {
             return func.apply(this, arguments);
           }
 
-          return func(this.parser.parseInline(token.tokens));
+          return func.call(this, this.parser.parseInline(token.tokens));
         };
       case 'escape':
-        return function(token: Tokens.Escape) {
+        return function(this: _Renderer, token: Tokens.Escape) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(token.text);
+          return func.call(this, token.text);
         };
       case 'link':
         return function(this: _Renderer, token: Tokens.Link) {
@@ -431,17 +433,17 @@ export class Marked {
             return func.apply(this, arguments);
           }
 
-          return func(token.href, token.title, this.parser.parseInline(token.tokens));
+          return func.call(this, token.href, token.title, this.parser.parseInline(token.tokens));
         };
       case 'image':
-        return function(token: Tokens.Image) {
+        return function(this: _Renderer, token: Tokens.Image) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(token.href, token.title, token.text);
+          return func.call(this, token.href, token.title, token.text);
         };
       case 'strong':
         return function(this: _Renderer, token: Tokens.Strong) {
@@ -451,7 +453,7 @@ export class Marked {
             return func.apply(this, arguments);
           }
 
-          return func(this.parser.parseInline(token.tokens));
+          return func.call(this, this.parser.parseInline(token.tokens));
         };
       case 'em':
         return function(this: _Renderer, token: Tokens.Em) {
@@ -461,17 +463,17 @@ export class Marked {
             return func.apply(this, arguments);
           }
 
-          return func(this.parser.parseInline(token.tokens));
+          return func.call(this, this.parser.parseInline(token.tokens));
         };
       case 'codespan':
-        return function(token: Tokens.Codespan) {
+        return function(this: _Renderer, token: Tokens.Codespan) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(token.text);
+          return func.call(this, token.text);
         };
       case 'del':
         return function(this: _Renderer, token: Tokens.Del) {
@@ -481,17 +483,17 @@ export class Marked {
             return func.apply(this, arguments);
           }
 
-          return func(this.parser.parseInline(token.tokens));
+          return func.call(this, this.parser.parseInline(token.tokens));
         };
       case 'text':
-        return function(token: Tokens.Text) {
+        return function(this: _Renderer, token: Tokens.Text) {
           if (!token.type || token.type !== prop) {
             // @ts-ignore
             // eslint-disable-next-line prefer-rest-params
             return func.apply(this, arguments);
           }
 
-          return func(token.text);
+          return func.call(this, token.text);
         };
       default:
         // do nothing
diff --git a/src/MarkedOptions.ts b/src/MarkedOptions.ts
index 8b0d0ea7..591ac3bc 100644
--- a/src/MarkedOptions.ts
+++ b/src/MarkedOptions.ts
@@ -36,17 +36,17 @@ export type TokenizerAndRendererExtension = TokenizerExtension | RendererExtensi
 
 type HooksApi = Omit<_Hooks, 'constructor' | 'options'>;
 type HooksObject = {
-  [K in keyof HooksApi]?: (...args: Parameters<HooksApi[K]>) => ReturnType<HooksApi[K]> | Promise<ReturnType<HooksApi[K]>>
+  [K in keyof HooksApi]?: (this: _Hooks, ...args: Parameters<HooksApi[K]>) => ReturnType<HooksApi[K]> | Promise<ReturnType<HooksApi[K]>>
 };
 
 type RendererApi = Omit<_Renderer, 'constructor' | 'options' | 'parser'>;
 type RendererObject = {
-  [K in keyof RendererApi]?: (...args: Parameters<RendererApi[K]>) => ReturnType<RendererApi[K]> | false
+  [K in keyof RendererApi]?: (this: _Renderer, ...args: Parameters<RendererApi[K]>) => ReturnType<RendererApi[K]> | false
 };
 
 type TokenizerApi = Omit<_Tokenizer, 'constructor' | 'options' | 'rules' | 'lexer'>;
 type TokenizerObject = {
-  [K in keyof TokenizerApi]?: (...args: Parameters<TokenizerApi[K]>) => ReturnType<TokenizerApi[K]> | false
+  [K in keyof TokenizerApi]?: (this: _Tokenizer, ...args: Parameters<TokenizerApi[K]>) => ReturnType<TokenizerApi[K]> | false
 };
 
 export interface MarkedExtension {
diff --git a/test/types/marked.ts b/test/types/marked.ts
index b8d373bb..607fbf50 100644
--- a/test/types/marked.ts
+++ b/test/types/marked.ts
@@ -136,9 +136,9 @@ marked.use({ renderer }, { tokenizer });
 
 marked.use({
   renderer: {
-    heading({ text, depth }) {
+    heading({ tokens, depth }) {
       if (depth > 3) {
-        return `<p>${text}</p>`;
+        return `<p>${this.parser.parseInline(tokens)}</p>`;
       }
 
       return false;
@@ -149,6 +149,20 @@ marked.use({
     }
   },
   tokenizer: {
+    heading(src) {
+      const cap = this.rules.block.heading.exec(src);
+      if (cap) {
+        let text = cap[2].trim();
+
+        return {
+          type: 'heading',
+          raw: cap[0],
+          depth: cap[1].length,
+          text,
+          tokens: this.lexer.inline(text)
+        };
+      }
+    },
     codespan(src) {
       const match = src.match(/\$+([^\$\n]+?)\$+/);
       if (match) {
@@ -317,6 +331,9 @@ marked.use({ tokenizer: new Tokenizer() });
 marked.use({
   hooks: {
     preprocess(markdown) {
+      if (this.options.async) {
+        return Promise.resolve(markdown);
+      }
       return markdown;
     },
     postprocess(html) {