Reuse argValues

Block args set by fields are static and never change. Inputs that do
change are always set onto args. With these two assumptions we can
reuse the same objects for each execution of the same block instead of
constantly creating them and letting them be garbage collected.

src/engine/execute.js

@@ -201,21 +201,43 @@ const execute = function (sequencer, thread, recursiveCall) {
         blockCached._fieldKind = fieldKeys.length > 0 ? FieldKind.DYNAMIC : FieldKind.NONE;
         if (fieldKeys.length === 1 && fieldKeys.includes('VARIABLE')) {
             blockCached._fieldKind = FieldKind.VARIABLE;
-            blockCached._fieldVariable = {
+            blockCached._argValues = {
+                VARIABLE: {
                     id: fields.VARIABLE.id,
                     name: fields.VARIABLE.value
+                },
+                mutation: blockCached.mutation
             };
         } else if (fieldKeys.length === 1 && fieldKeys.includes('LIST')) {
             blockCached._fieldKind = FieldKind.LIST;
-            blockCached._fieldList = {
+            blockCached._argValues = {
+                LIST: {
                     id: fields.LIST.id,
                     name: fields.LIST.value
+                },
+                mutation: blockCached.mutation
             };
         } else if (fieldKeys.length === 1 && fieldKeys.includes('BROADCAST_OPTION')) {
             blockCached._fieldKind = FieldKind.BROADCAST_OPTION;
-            blockCached._fieldBroadcastOption = {
+            blockCached._argValues = {
+                BROADCAST_OPTION: {
                     id: fields.BROADCAST_OPTION.id,
                     name: fields.BROADCAST_OPTION.value
+                },
+                mutation: blockCached.mutation
+            };
+        } else if (fieldKeys.length > 0) {
+            // FieldKind.DYNAMIC
+            blockCached._argValues = {
+                mutation: blockCached.mutation
+            };
+            for (const fieldName in fields) {
+                blockCached._argValues[fieldName] = fields[fieldName].value;
+            }
+        } else {
+            // FieldKind.NONE
+            blockCached._argValues = {
+                mutation: blockCached.mutation
             };
         }
 
@@ -228,9 +250,7 @@ const execute = function (sequencer, thread, recursiveCall) {
     }
 
     const opcode = blockCached.opcode;
-    const fields = blockCached._fields;
     const inputs = blockCached._inputs;
-    const mutation = blockCached.mutation;
     const blockFunction = blockCached._blockFunction;
     const isHat = blockCached._isHat;
 
@@ -260,29 +280,10 @@ const execute = function (sequencer, thread, recursiveCall) {
         return;
     }
 
-    // Generate values for arguments (inputs).
+    // Update values for arguments (inputs).
-    const argValues = {};
+    let argValues = blockCached._argValues;
 
-    // Add all fields on this block to the argValues. Some known fields may
+    // Fields are set during blockCached initialization.
-    // appear by themselves and can be set to argValues quicker by setting them
-    // explicitly.
-    if (blockCached._fieldKind !== FieldKind.NONE) {
-        switch (blockCached._fieldKind) {
-        case FieldKind.VARIABLE:
-            argValues.VARIABLE = blockCached._fieldVariable;
-            break;
-        case FieldKind.LIST:
-            argValues.LIST = blockCached._fieldList;
-            break;
-        case FieldKind.BROADCAST_OPTION:
-            argValues.BROADCAST_OPTION = blockCached._fieldBroadcastOption;
-            break;
-        default:
-            for (const fieldName in fields) {
-                argValues[fieldName] = fields[fieldName].value;
-            }
-        }
-    }
 
     // Recursively evaluate input blocks.
     for (const inputName in inputs) {
@@ -363,9 +364,6 @@ const execute = function (sequencer, thread, recursiveCall) {
         }
     }
 
-    // Add any mutation to args (e.g., for procedures).
-    argValues.mutation = mutation;
-
     let primitiveReportedValue = null;
     blockUtility.sequencer = sequencer;
     blockUtility.thread = thread;