WIP optimization

Author: philippfromme

lib/TaskExecution.js

@@ -140,6 +140,10 @@ export default class TaskExecution extends EventEmitter {
     // Collect IDs of direct children of the tested element
     const childElementIds = getChildElementIds(this._elementRegistry, element.id);
 
+    // Track last emitted items to avoid re-emitting unchanged entries
+    let lastWaitingItemsKey = null;
+    let lastChildrenItemsKey = null;
+
     const intervalCallback = async () => {
       const getProcessInstanceResult = await this._api.getProcessInstance(processInstanceKey);
 
@@ -162,7 +166,10 @@ export default class TaskExecution extends EventEmitter {
       const waitingItems = buildWaitingItems(jobsResult, userTasksResult, messageSubscriptionsResult, elementInstancesResult);
       enrichEventSubProcessChildren(waitingItems, elementInstancesResult, this._elementRegistry);
 
-      if (waitingItems.length) {
+      const waitingItemsKey = getItemsKey(waitingItems);
+
+      if (waitingItems.length && waitingItemsKey !== lastWaitingItemsKey) {
+        lastWaitingItemsKey = waitingItemsKey;
 
         /** @type {import('./types').ExecutionLogEntry} */
         const logEntry = {
@@ -171,6 +178,8 @@ export default class TaskExecution extends EventEmitter {
           timestamp: Date.now()
         };
         this.emit('taskExecution.log', logEntry);
+      } else if (!waitingItems.length) {
+        lastWaitingItemsKey = null;
       }
 
       // Poll for current variables
@@ -189,12 +198,20 @@ export default class TaskExecution extends EventEmitter {
 
       // Emit child elements (sub-process internals) enriched with variables
       const childElements = buildChildElements(elementInstancesResult, element.id, childElementIds);
-      if (childElements.length) {
+      const enrichedChildren = childElements.length
+        ? enrichChildrenWithVariables(childElements, elementInstancesResult, getVariablesResult)
+        : [];
+      const childrenItemsKey = getItemsKey(enrichedChildren);
+
+      if (enrichedChildren.length && childrenItemsKey !== lastChildrenItemsKey) {
+        lastChildrenItemsKey = childrenItemsKey;
         this.emit('taskExecution.log', {
           type: 'children',
-          items: enrichChildrenWithVariables(childElements, elementInstancesResult, getVariablesResult),
+          items: enrichedChildren,
           timestamp: Date.now()
         });
+      } else if (!enrichedChildren.length) {
+        lastChildrenItemsKey = null;
       }
 
       if (!getProcessInstanceResult.success) {
@@ -752,4 +769,15 @@ function enrichChildrenWithVariables(children, elementInstancesResult, variables
 
     return { ...child, variables: childVars };
   });
+}
+
+/**
+ * Create a stable key from items for change detection.
+ * Only emits a new log entry when this key differs from the previous one.
+ *
+ * @param {Array} items
+ * @returns {string}
+ */
+function getItemsKey(items) {
+  return JSON.stringify(items);
 }