Do not over-prune var data cache (#1198)

* Remove unused variables and imports

* Simplify conditional

* Fix typo

* Do not overprune var data cache

There is a bug in how the universe and world gene sets are constructed
and passed to `ControlsHelpers.pruneVarDataCache` that causes the var
data cache to be over-pruned. This commit fixes the issue.

Consider the following example from the node console:

```
❯ node
Welcome to Node.js v13.5.0.
Type ".help" for more information.
> new Set([1], [2], [3])
Set(1) { 1 }
```

What we really want is the set `Set(3) { 1, 2, 3 }`, which can be
constructed as:

```
> new Set([].concat([1], [2], [3]))
Set(3) { 1, 2, 3 }
```

client/src/reducers/controls.js

@@ -1,7 +1,6 @@
 // jshint esversion: 6
 
 import _ from "lodash";
-import * as globals from "../globals";
 import { subsetAndResetGeneLists } from "../util/stateManager/controlsHelpers";
 
 const Controls = (

client/src/reducers/undoable.js

@@ -221,15 +221,15 @@ const Undoable = (reducer, undoableKeys, options = {}) => {
     const aType = action.type;
     switch (aType) {
       case "@@undoable/undo": {
-        return undo(currentState, action);
+        return undo(currentState);
       }
 
       case "@@undoable/redo": {
-        return redo(currentState, action);
+        return redo(currentState);
       }
 
       case "@@undoable/clear": {
-        return clear(currentState, action);
+        return clear(currentState);
       }
 
       default: {

client/src/reducers/undoableConfig.js

@@ -145,7 +145,7 @@ Signature:  (fsm, event, from) => undoableAction
 const onFsmError = (fsm, event, from) => {
   console.error(`FSM error [event: "${event}", state: "${from}"]`, fsm);
   // In production, try to recover gracefully if we have unexpected state
-  return clear(fsm);
+  return clear();
 };
 
 /*

client/src/reducers/universe.js

@@ -62,9 +62,7 @@ const Universe = (state = null, action, nextSharedState, prevSharedState) => {
       const { userDefinedGenes, diffexpGenes } = prevSharedState;
       const allTheGenesWeNeed = [
         ...new Set(
-          userDefinedGenes,
-          diffexpGenes,
-          Object.keys(action.expressionData)
+          [userDefinedGenes, diffexpGenes, Object.keys(action.expressionData)].filter(ele => ele).flat()
         )
       ];
       varData = ControlsHelpers.pruneVarDataCache(varData, allTheGenesWeNeed);

client/src/reducers/world.js

@@ -101,15 +101,10 @@ const WorldReducer = (
       const { userDefinedGenes, diffexpGenes } = prevSharedState;
       const allTheGenesWeNeed = [
         ...new Set(
-          userDefinedGenes,
-          diffexpGenes,
-          Object.keys(action.expressionData)
+          [userDefinedGenes, diffexpGenes, Object.keys(action.expressionData)].filter(ele => ele).flat()
         )
       ];
-      unclippedVarData = ControlsHelpers.pruneVarDataCache(
-        unclippedVarData,
-        allTheGenesWeNeed
-      );
+      unclippedVarData = ControlsHelpers.pruneVarDataCache(unclippedVarData, allTheGenesWeNeed);
 
       // at this point, we have the unclipped data in unclippedVarData.
       // Now create clipped.