Install scripts, build app with rollup & configurable mirror app id

app/rollup/no-memcpy-plugin.js

@@ -0,0 +1,34 @@
+import MagicString from 'magic-string';
+
+const MEMCPY_REQUIRE_STRING = 'require("memcpy")';
+const REPLACEMENT_STRING = 'null';
+
+// We're doing this because memcpy is an optional dependency of ByteBufferNB,
+// but Rollup doesn't understand optional dependencies and tries to use it.
+// We can't simply use memcpy, because it has native code for older versions of
+// Node and no longer builds!
+export default (variant) => {
+    let mainId = null;
+
+    return {
+        name: 'no-memcpy-plugin'
+      , transform: (code, id) => {
+            if (id.endsWith('ByteBufferNB.js')) {
+                const start = code.indexOf(MEMCPY_REQUIRE_STRING);
+
+                if (start >= 0) {
+                    const magicString = new MagicString(code);
+                    const end = start + MEMCPY_REQUIRE_STRING.length;
+                    magicString.overwrite(start, end, REPLACEMENT_STRING);
+
+                    return {
+                        code: magicString.toString()
+                      , map: magicString.generateMap()
+                    };
+                }
+            }
+
+            return null;
+        }
+    }
+}