MD Bookmarks: Implement item selection in new data flow system

chrome/browser/resources/md_bookmarks/reducers.js

Index: chrome/browser/resources/md_bookmarks/reducers.js
diff --git a/chrome/browser/resources/md_bookmarks/reducers.js b/chrome/browser/resources/md_bookmarks/reducers.js
index ca13ab5cd7c1e820662349656f45aae15251c25a..05d6262905fd490dda07dabc298d70027fcbfb5d 100644
--- a/chrome/browser/resources/md_bookmarks/reducers.js
+++ b/chrome/browser/resources/md_bookmarks/reducers.js
@@ -10,6 +10,56 @@
  */
 
 cr.define('bookmarks', function() {
+  var SelectionState = {};
+
+  /**
+   * @param {SelectionState} selectionState
+   * @param {Action} action
+   * @return {SelectionState}
+   */
+  SelectionState.selectItems = function(selectionState, action) {
+    var newState = {};

[calamity, 2017/03/14 03:01:45]

nit: newItems

[tsergeant, 2017/03/14 05:42:02]

Done.

+    if (action.add)
+      Object.assign(newState, selectionState.items);
+
+    action.items.forEach(function(id) {
+      newState[id] = true;
+    });
+
+    return /** @type {SelectionState} */ (Object.assign({}, selectionState, {
+      items: newState,
+      anchor: action.anchor,
+    }));
+  };
+
+  /**
+   * @param {SelectionState} selectionState
+   * @return {SelectionState}
+   */
+  SelectionState.deselectAll = function(selectionState) {
+    return {
+      count: 0,

[calamity, 2017/03/14 03:01:45]

Is count used anywhere? Or is it just like, a #define for 0 =P

[tsergeant, 2017/03/14 05:42:02]

I kept meaning to either implement it or remove it for now, but forgot.

Removed for now, but we'll need it eventually.

+      items: {},
+      anchor: null,
+    };
+  };
+
+  /**
+   * @param {SelectionState} selection
+   * @param {Action} action
+   * @return {SelectionState}
+   */
+  SelectionState.updateSelection = function(selection, action) {
+    switch (action.name) {
+      case 'select-folder':
+      case 'finish-search':

[calamity, 2017/03/14 03:01:45]

Also clear-search.

+Test

[tsergeant, 2017/03/14 05:42:02]

Done.

+        return SelectionState.deselectAll(selection);
+      case 'select-items':
+        return SelectionState.selectItems(selection, action);

[calamity, 2017/03/14 03:01:45]

What happens to removed anchor indexes? They'll explode on the next shift
select, right?

[tsergeant, 2017/03/14 05:42:02]

Yup, again, that's something that's was fixed in the follow-up.

For now, I've made the action not assert in this case: It will just select the
single item if the anchor item is missing, and I've added a test.

+    }
+    return selection;
+  };
+
   var SearchState = {};
 
   /**
@@ -243,6 +293,7 @@ cr.define('bookmarks', function() {
       closedFolders: ClosedFolderState.updateClosedFolders(
           state.closedFolders, action, state.nodes),
       search: SearchState.updateSearch(state.search, action),
+      selection: SelectionState.updateSelection(state.selection, action),
     };
   }
 
@@ -252,5 +303,6 @@ cr.define('bookmarks', function() {
     NodeState: NodeState,
     SearchState: SearchState,
     SelectedFolderState: SelectedFolderState,
+    SelectionState: SelectionState,
   };
 });