From 17dc7d313c29f1532c6c6e9ce3e4f1cda793094f Mon Sep 17 00:00:00 2001
From: Joe Heffernan <interim17@gmail.com>
Date: Thu, 13 Jun 2024 09:51:37 -0700
Subject: [PATCH] Fix/null agent function (#396)

* use function to get null agent

* use createNullAgent in viewer

* nullAgent instead of createNullAgent

* unused import
---
 examples/src/Viewer.tsx   |  4 ++--
 src/constants.ts          | 26 ++++++++++++++------------
 src/index.ts              |  1 +
 src/simularium/VisData.ts |  4 ++--
 src/visGeometry/index.ts  |  4 ++--
 5 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/examples/src/Viewer.tsx b/examples/src/Viewer.tsx
index 887891c1..80c8a803 100644
--- a/examples/src/Viewer.tsx
+++ b/examples/src/Viewer.tsx
@@ -8,7 +8,7 @@ import type {
     SelectionStateInfo,
     SelectionEntry,
 } from "../../type-declarations";
-import { NULL_AGENT, TrajectoryType } from "../../src/constants";
+import { nullAgent, TrajectoryType } from "../../src/constants";
 import SimulariumViewer, {
     SimulariumController,
     RenderStyle,
@@ -175,7 +175,7 @@ const initialState: ViewerState = {
     trajectoryTitle: "",
     initialPlay: true,
     firstFrameTime: 0,
-    followObjectData: NULL_AGENT,
+    followObjectData: nullAgent(),
 };
 
 class Viewer extends React.Component<InputParams, ViewerState> {
diff --git a/src/constants.ts b/src/constants.ts
index 597d18c3..42c7f026 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -34,16 +34,18 @@ export const enum TrajectoryType {
 
 export const DEFAULT_FRAME_RATE = 60; // frames per second
 
-export const NULL_AGENT: AgentData = {
-    "vis-type": -1,
-    instanceId: -1,
-    type: -1,
-    x: 0,
-    y: 0,
-    z: 0,
-    xrot: 0,
-    yrot: 0,
-    zrot: 0,
-    cr: 0,
-    subpoints: [],
+export const nullAgent = (): AgentData => {
+    return {
+        "vis-type": -1,
+        instanceId: -1,
+        type: -1,
+        x: 0,
+        y: 0,
+        z: 0,
+        xrot: 0,
+        yrot: 0,
+        zrot: 0,
+        cr: 0,
+        subpoints: [],
+    };
 };
diff --git a/src/index.ts b/src/index.ts
index fa7a74c5..7625c064 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -28,5 +28,6 @@ export {
 } from "./simularium";
 export { compareTimes, loadSimulariumFile } from "./util";
 export { DEFAULT_CAMERA_SPEC } from "./constants";
+export { AgentData } from "./simularium/types";
 
 export default Viewport;
diff --git a/src/simularium/VisData.ts b/src/simularium/VisData.ts
index 4f808a13..ea491f2d 100644
--- a/src/simularium/VisData.ts
+++ b/src/simularium/VisData.ts
@@ -14,7 +14,7 @@ import {
 import { FrontEndError, ErrorLevel } from "./FrontEndError";
 import type { ParsedBundle } from "./VisDataParse";
 import { parseVisDataMessage } from "./VisDataParse";
-import { NULL_AGENT } from "../constants";
+import { nullAgent } from "../constants";
 
 class VisData {
     private frameCache: AgentData[][];
@@ -49,7 +49,7 @@ class VisData {
         let j = AGENTS_OFFSET;
         for (let i = 0; i < expectedNumAgents; i++) {
             //TODO use visType in AgentData and convert from "vis-type" here at parse time
-            const agentData: AgentData = { ...NULL_AGENT };
+            const agentData: AgentData = nullAgent();
 
             for (let k = 0; k < AGENT_OBJECT_KEYS.length; ++k) {
                 agentData[AGENT_OBJECT_KEYS[k]] = floatView[j++];
diff --git a/src/visGeometry/index.ts b/src/visGeometry/index.ts
index f9d97c35..fab9cb73 100644
--- a/src/visGeometry/index.ts
+++ b/src/visGeometry/index.ts
@@ -41,7 +41,7 @@ import { FrontEndError, ErrorLevel } from "../simularium/FrontEndError";
 import {
     DEFAULT_CAMERA_Z_POSITION,
     DEFAULT_CAMERA_SPEC,
-    NULL_AGENT,
+    nullAgent,
 } from "../constants";
 import {
     AgentData,
@@ -653,7 +653,7 @@ class VisGeometry {
     public getObjectData(id: number): AgentData {
         const data = this.visAgentInstances.get(id);
         if (!data) {
-            return NULL_AGENT;
+            return nullAgent();
         }
         return data.agentData;
     }