1 files changed, 22 insertions, 0 deletions
diff --git a/devtools/client/memory/reducers/tree-map-display.js b/devtools/client/memory/reducers/tree-map-display.js
new file mode 100644
index 0000000000..7f145e8181
--- /dev/null
+++ b/devtools/client/memory/reducers/tree-map-display.js
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {
+  actions,
+  treeMapDisplays,
+} = require("resource://devtools/client/memory/constants.js");
+const DEFAULT_TREE_MAP_DISPLAY = treeMapDisplays.coarseType;
+
+const handlers = Object.create(null);
+
+handlers[actions.SET_TREE_MAP_DISPLAY] = function (_, { display }) {
+  return display;
+};
+
+module.exports = function (state = DEFAULT_TREE_MAP_DISPLAY, action) {
+  const handler = handlers[action.type];
+  return handler ? handler(state, action) : state;
+};