Fixes #2267

src/Engines/Custom.js

@@ -165,12 +165,15 @@ class CustomEngine extends TemplateEngine {
       defaultRenderer, // bind defaultRenderer to compile function
     })(str, inputPath);
 
-    // Bind defaultRenderer to render function
-    if ("then" in fn && typeof fn.then === "function") {
-      // Promise, wait to bind
-      return fn.then((fn) => fn.bind({ defaultRenderer }));
-    } else if ("bind" in fn && typeof fn.bind === "function") {
-      return fn.bind({ defaultRenderer });
+    // Support `undefined` to skip compile/render
+    if (fn) {
+      // Bind defaultRenderer to render function
+      if ("then" in fn && typeof fn.then === "function") {
+        // Promise, wait to bind
+        return fn.then((fn) => fn.bind({ defaultRenderer }));
+      } else if ("bind" in fn && typeof fn.bind === "function") {
+        return fn.bind({ defaultRenderer });
+      }
     }
 
     return fn;

test/TemplateRenderCustomTest.js

@@ -215,3 +215,19 @@ test("JavaScript functions should not be mutable but not *that* mutable", async
   let data = await tmpl.getData();
   t.is(await tmpl.render(data), "<p>Paragraph</p>");
 });
+
+test("Return undefined in compile to ignore #2267", async (t) => {
+  let eleventyConfig = new TemplateConfig();
+  eleventyConfig.userConfig.extensionMap.add({
+    extension: "txt",
+    key: "txt",
+    compile: function (str, inputPath) {
+      return;
+    },
+  });
+
+  let tr = getNewTemplateRender("txt", null, eleventyConfig);
+
+  let fn = await tr.getCompiledTemplate("<p>Paragraph</p>");
+  t.is(fn, undefined);
+});

test/TemplateTest-CustomExtensions.js

@@ -438,3 +438,31 @@ test("Access to default renderer when you override an existing extension (async
   let data = await tmpl.getData();
   t.is(await tmpl.render(data), "hi");
 });
+
+test("Return undefined in compile to ignore #2267", async (t) => {
+  let eleventyConfig = new TemplateConfig();
+  eleventyConfig.userConfig.extensionMap.add({
+    extension: "txt",
+    key: "txt",
+    compileOptions: {
+      cache: false,
+    },
+    getData: false,
+    compile: function (str, inputPath) {
+      return;
+    },
+  });
+
+  let dataObj = new TemplateData("./test/stubs/", eleventyConfig);
+  let tmpl = getNewTemplate(
+    "./test/stubs/custom-extension.txt",
+    "./test/stubs/",
+    "dist",
+    dataObj,
+    null,
+    eleventyConfig
+  );
+
+  let data = await tmpl.getData();
+  t.is(await tmpl.render(data), undefined);
+});