return false to use last renderer/tokenizer

docs/USING_PRO.md

@@ -111,8 +111,9 @@ const tokenizer = {
         text: match[1].trim()
       };
     }
-    const originalTokenizer = new marked.Tokenizer(this.options);
-    return originalTokenizer.codespan.apply(this, arguments);
+
+    // return false to use original codespan renderer
+    return false;
   }
 };
 

src/marked.js

@@ -136,14 +136,28 @@ marked.use = function(extension) {
   if (extension.renderer) {
     const renderer = marked.defaults.renderer || new Renderer();
     for (const prop in extension.renderer) {
-      renderer[prop] = extension.renderer[prop];
+      const prevRenderer = renderer[prop];
+      renderer[prop] = (...args) => {
+        let ret = extension.renderer[prop].apply(renderer, args);
+        if (ret === false) {
+          ret = prevRenderer.apply(renderer, args);
+        }
+        return ret;
+      };
     }
     opts.renderer = renderer;
   }
   if (extension.tokenizer) {
     const tokenizer = marked.defaults.tokenizer || new Tokenizer();
     for (const prop in extension.tokenizer) {
-      tokenizer[prop] = extension.tokenizer[prop];
+      const prevTokenizer = tokenizer[prop];
+      tokenizer[prop] = (...args) => {
+        let ret = extension.tokenizer[prop].apply(tokenizer, args);
+        if (ret === false) {
+          ret = prevTokenizer.apply(tokenizer, args);
+        }
+        return ret;
+      };
     }
     opts.tokenizer = tokenizer;
   }

test/unit/marked-spec.js

@@ -171,6 +171,39 @@ paragraph
     expect(html).toBe('extension2 paragraph\nextension1 html\n<h1 id="heading">heading</h1>\n');
   });
 
+  it('should use previous extension when returning false', () => {
+    const extension1 = {
+      renderer: {
+        paragraph(text) {
+          if (text !== 'original') {
+            return 'extension1 paragraph\n';
+          }
+          return false;
+        }
+      }
+    };
+    const extension2 = {
+      renderer: {
+        paragraph(text) {
+          if (text !== 'extension1' && text !== 'original') {
+            return 'extension2 paragraph\n';
+          }
+          return false;
+        }
+      }
+    };
+    marked.use(extension1);
+    marked.use(extension2);
+    const html = marked(`
+paragraph
+
+extension1
+
+original
+`);
+    expect(html).toBe('extension2 paragraph\nextension1 paragraph\n<p>original</p>\n');
+  });
+
   it('should get options with this.options', () => {
     const extension = {
       renderer: {