diff --git a/.github/workflows/nodejs.yml b/.github/workflows/nodejs.yml
index a5a8b822..10ca6b7f 100644
--- a/.github/workflows/nodejs.yml
+++ b/.github/workflows/nodejs.yml
@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        node-version: [10.x, 12.x]
+        node-version: [12.x, 14.x]
 
     runs-on: ${{ matrix.os }}
 
diff --git a/src/constant.js b/src/constant.js
deleted file mode 100644
index b7d42e71..00000000
--- a/src/constant.js
+++ /dev/null
@@ -1,5 +0,0 @@
-export default function(x) {
-  return function() {
-    return x;
-  };
-}
diff --git a/src/library.js b/src/library.js
index 0700f669..476e6fd6 100644
--- a/src/library.js
+++ b/src/library.js
@@ -1,5 +1,4 @@
 import {require as requireDefault} from "d3-require";
-import constant from "./constant.js";
 import DOM from "./dom/index.js";
 import Files from "./files/index.js";
 import {NoFileAttachments} from "./fileAttachment.js";
@@ -13,24 +12,39 @@ import resolve from "./resolve.js";
 import requirer from "./require.js";
 import svg from "./svg.js";
 import tex from "./tex.js";
+import vegalite from "./vegalite.js";
 import width from "./width.js";
 
 export default Object.assign(function Library(resolver) {
   const require = requirer(resolver);
-  Object.defineProperties(this, {
-    DOM: {value: DOM, writable: true, enumerable: true},
-    FileAttachment: {value: constant(NoFileAttachments), writable: true, enumerable: true},
-    Files: {value: Files, writable: true, enumerable: true},
-    Generators: {value: Generators, writable: true, enumerable: true},
-    html: {value: constant(html), writable: true, enumerable: true},
-    md: {value: md(require), writable: true, enumerable: true},
-    Mutable: {value: constant(Mutable), writable: true, enumerable: true},
-    now: {value: now, writable: true, enumerable: true},
-    Promises: {value: Promises, writable: true, enumerable: true},
-    require: {value: constant(require), writable: true, enumerable: true},
-    resolve: {value: constant(resolve), writable: true, enumerable: true},
-    svg: {value: constant(svg), writable: true, enumerable: true},
-    tex: {value: tex(require), writable: true, enumerable: true},
-    width: {value: width, writable: true, enumerable: true}
-  });
+  Object.defineProperties(this, properties({
+    DOM: () => DOM,
+    FileAttachment: () => NoFileAttachments,
+    Files: () => Files,
+    Generators: () => Generators,
+    Inputs: () => require("@observablehq/inputs@0.8.0/dist/inputs.umd.min.js"),
+    Mutable: () => Mutable,
+    Plot: () => require("@observablehq/plot@0.1.0/dist/plot.umd.min.js"),
+    Promises: () => Promises,
+    _: () => require("lodash@4.17.21/lodash.min.js"),
+    d3: () => require("d3@6.7.0/dist/d3.min.js"),
+    htl: () => require("htl@0.2.5/dist/htl.min.js"),
+    html: () => html,
+    md: md(require),
+    now: now,
+    require: () => require,
+    resolve: () => resolve,
+    svg: () => svg,
+    tex: tex(require),
+    vl: vegalite(require),
+    width: width
+  }));
 }, {resolve: requireDefault.resolve});
+
+function properties(values) {
+  return Object.fromEntries(Object.entries(values).map(property));
+}
+
+function property([key, value]) {
+  return [key, ({value, writable: true, enumerable: true})];
+}
diff --git a/src/promises/when.js b/src/promises/when.js
index f7c6b880..d0fa3d7f 100644
--- a/src/promises/when.js
+++ b/src/promises/when.js
@@ -1,5 +1,3 @@
-import constant from "../constant.js";
-
 var timeouts = new Map;
 
 function timeout(now, time) {
@@ -16,7 +14,7 @@ function timeout(now, time) {
 
 export default function when(time, value) {
   var now;
-  return (now = timeouts.get(time = +time)) ? now.then(constant(value))
+  return (now = timeouts.get(time = +time)) ? now.then(() => value)
       : (now = Date.now()) >= time ? Promise.resolve(value)
-      : timeout(now, time).then(constant(value));
+      : timeout(now, time).then(() => value);
 }
diff --git a/src/vegalite.js b/src/vegalite.js
new file mode 100644
index 00000000..96ddc914
--- /dev/null
+++ b/src/vegalite.js
@@ -0,0 +1,10 @@
+export default function vl(require) {
+  return async () => {
+    const [vega, vegalite, api] = await Promise.all([
+      "vega@5.20.2/build/vega.min.js",
+      "vega-lite@5.1.0/build/vega-lite.min.js",
+      "vega-lite-api@5.0.0/build/vega-lite-api.min.js"
+    ].map(module => require(module)));
+    return api.register(vega, vegalite);
+  };
+}
diff --git a/test/index-test.js b/test/index-test.js
index e15868b6..60d805bd 100644
--- a/test/index-test.js
+++ b/test/index-test.js
@@ -7,8 +7,13 @@ test("new Library returns a library with the expected keys", async t => {
     "FileAttachment",
     "Files",
     "Generators",
+    "Inputs",
     "Mutable",
+    "Plot",
     "Promises",
+    "_",
+    "d3",
+    "htl",
     "html",
     "md",
     "now",
@@ -16,6 +21,7 @@ test("new Library returns a library with the expected keys", async t => {
     "resolve",
     "svg",
     "tex",
+    "vl",
     "width"
   ]);
   t.end();