diff --git a/src/Engines/JavaScript.js b/src/Engines/JavaScript.js
index 82abcf35e..3dac80265 100644
--- a/src/Engines/JavaScript.js
+++ b/src/Engines/JavaScript.js
@@ -8,6 +8,10 @@ const EventBusUtil = require("../Util/EventBusUtil");
 class JavaScriptTemplateNotDefined extends EleventyBaseError {}
 
 class JavaScript extends TemplateEngine {
+  // which data keys to bind to `this` in JavaScript template functions
+  // static DATA_KEYS_TO_BIND = ["page", "eleventy"];
+  static DATA_KEYS_TO_BIND = ["page", "eleventy"];
+
   constructor(name, dirs, config) {
     super(name, dirs, config);
     this.instances = {};
@@ -50,7 +54,9 @@ class JavaScript extends TemplateEngine {
         }
         return new mod();
       } else {
-        return { render: mod };
+        return {
+          render: mod,
+        };
       }
     } else if ("data" in mod || "render" in mod) {
       if (!("render" in mod)) {
@@ -67,7 +73,6 @@ class JavaScript extends TemplateEngine {
 
     const mod = require(TemplatePath.absolutePath(inputPath));
     let inst = this._getInstance(mod);
-
     if (inst) {
       this.instances[inputPath] = inst;
     } else {
@@ -110,11 +115,10 @@ class JavaScript extends TemplateEngine {
 
   static wrapJavaScriptFunction(inst, fn) {
     return function (...args) {
-      if (inst && inst.page) {
-        this.page = inst.page;
-      }
-      if (inst && inst.eleventy) {
-        this.eleventy = inst.eleventy;
+      for (let key of JavaScript.DATA_KEYS_TO_BIND) {
+        if (inst && inst[key]) {
+          this[key] = inst[key];
+        }
       }
 
       return fn.call(this, ...args);
@@ -136,9 +140,13 @@ class JavaScript extends TemplateEngine {
         // TODO does this do anything meaningful for non-classes?
         // `inst` should have a normalized `render` function from _getInstance
 
-        // only blow away existing inst.page if it has a page.url
-        if (!inst.page || inst.page.url) {
-          inst.page = data.page;
+        for (let key of JavaScript.DATA_KEYS_TO_BIND) {
+          if (!inst[key] && data[key]) {
+            // only blow away existing inst.page if it has a page.url
+            if (key !== "page" || !inst.page || inst.page.url) {
+              inst[key] = data[key];
+            }
+          }
         }
         Object.assign(inst, this.getJavaScriptFunctions(inst));
 
diff --git a/test/EleventyTest.js b/test/EleventyTest.js
index 3611633b1..fd049cc75 100644
--- a/test/EleventyTest.js
+++ b/test/EleventyTest.js
@@ -693,3 +693,19 @@ test("Eleventy tag collection with spaces in the tag name, issue #2851", async (
   t.deepEqual(result.length, result[0].data.collections.all.length);
   t.deepEqual(result[0].data.collections["tag with spaces"].length, 1);
 });
+
+test("this.eleventy on JavaScript template functions, issue #2790", async (t) => {
+  t.plan(3);
+
+  let elev = new Eleventy("./test/stubs-2790", "./test/stubs-2790/_site", {
+    config: function (eleventyConfig) {
+      eleventyConfig.addJavaScriptFunction("jsfunction", function () {
+        t.truthy(this.eleventy);
+        return this.eleventy.generator.split(" ")[0];
+      });
+    },
+  });
+  let result = await elev.toJSON();
+  t.deepEqual(result.length, 1);
+  t.deepEqual(result[0].content, `<p>Eleventy</p>`);
+});
diff --git a/test/stubs-2790/page.11ty.js b/test/stubs-2790/page.11ty.js
new file mode 100644
index 000000000..026d69069
--- /dev/null
+++ b/test/stubs-2790/page.11ty.js
@@ -0,0 +1,3 @@
+module.exports = function ({ name }) {
+  return `<p>${this.jsfunction(name)}</p>`;
+};