renaming backend, cellxgene to server, client respectively

client/src/reducers/cells.js

@@ -0,0 +1,41 @@
+// jshint esversion: 6
+const Cells = (
+  state = {
+    cells: null /* world */,
+    loading: null,
+    error: null,
+
+    allCells: null /* this comes from cells endpoint, this is universe */
+  },
+  action
+) => {
+  switch (action.type) {
+    case "request cells started":
+      return Object.assign({}, state, {
+        loading: true,
+        error: null
+      });
+    case "request cells success":
+      return Object.assign({}, state, {
+        error: null,
+        loading: false,
+        cells: action.data, // most recently loaded cells
+
+        /* Universe - initialize once */
+        allCells: state.allCells ? state.allCells : action.data
+      });
+    case "request cells error":
+      return Object.assign({}, state, {
+        loading: false,
+        error: action.data
+      });
+    case "reset graph":
+      return Object.assign({}, state, {
+        cells: state.allCells
+      });
+    default:
+      return state;
+  }
+};
+
+export default Cells;