Load React + Emotion from CDN URLs, use globals

Remove @emotion/babel-preset-css-prop and import { jsx } from
@emotion/core directly instead so Rollup can preserve imports order when
bundling (instead of @emotion/core automatically inserting itself as the
first import).

modules/utils/getEntryPoint.js

@@ -0,0 +1,17 @@
+// Virtual module id; see rollup.config.js
+import entryManifest from 'entry-manifest';
+
+export default function getEntryPoint(name, format) {
+  let entryPoints;
+  entryManifest.forEach(manifest => {
+    if (name in manifest) {
+      entryPoints = manifest[name];
+    }
+  });
+
+  if (entryPoints) {
+    return entryPoints.find(e => e.format === format);
+  }
+
+  return null;
+}

modules/utils/getEntryPoints.js

@@ -1,19 +0,0 @@
-import invariant from 'invariant';
-
-// Virtual module id; see rollup.config.js
-import entryManifest from 'entry-manifest';
-
-export default function getEntryPoints(entryName, formatKeys) {
-  const manifest = entryManifest[entryName];
-
-  invariant(manifest, 'Invalid entry name: %s', entryName);
-
-  return manifest.reduce((memo, entryPoint) => {
-    if (entryPoint.format in formatKeys) {
-      const key = formatKeys[entryPoint.format];
-      memo[key] = entryPoint.url;
-    }
-
-    return memo;
-  }, {});
-}

modules/utils/getScripts.js

@@ -0,0 +1,16 @@
+import invariant from 'invariant';
+
+import getEntryPoint from './getEntryPoint';
+
+export default function getScripts(entryName, globalURLs) {
+  const entryPoint = getEntryPoint(entryName, 'iife');
+
+  invariant(entryPoint, 'Invalid entry name "%s"', entryName);
+
+  const globalScripts = entryPoint.globalImports.map(id => {
+    invariant(globalURLs[id], 'Missing global URL for id "%s"', id);
+    return globalURLs[id];
+  });
+
+  return globalScripts.concat(entryPoint.url);
+}