Implement code splitting for codemirror

client/dynamic-loader.js

@@ -0,0 +1,22 @@
+"use strict";
+
+let codeMirror;
+
+function loadCodeMirror() {
+  if (codeMirror) return Promise.resolve();
+
+  return new Promise((resolve, reject) => {
+    const promises = [
+      import(/* webpackChunkName: "codemirror" */ "codemirror"),
+      import(/* webpackChunkName: "codemirror" */ "codemirror/mode/javascript/javascript")
+    ];
+    Promise.all(promises)
+      .then(modules => {
+        codeMirror = modules[0];
+        resolve();
+      })
+      .catch(reject);
+  });
+}
+
+export { loadCodeMirror, codeMirror };