improve polling performance and remove unused updateContent module

app/assets/javascripts/activityChart.js

@@ -5,6 +5,9 @@
         const tableContainer = document.getElementById('activityContainer');
         const currentUserName = tableContainer.getAttribute('data-currentUserName');
         const currentServiceId = tableContainer.getAttribute('data-currentServiceId');
+        let pollInterval;
+        let isPolling = false;
+        const POLL_INTERVAL_MS = 25000;
         const COLORS = {
             delivered: '#0076d6',
             failed: '#fa9441',
@@ -153,8 +156,6 @@
             .on('mouseout', function() {
                 tooltip.style('display', 'none');
             })
-            .transition()
-            .duration(1000)
             .attr('y', d => y(d[1]))
             .attr('height', d => {
                 const calculatedHeight = y(d[0]) - y(d[1]);
@@ -209,28 +210,35 @@
         table.append(tbody);
     };
 
-    const fetchData = function(type) {
+    const fetchData = async function(type) {
+        if (isPolling) {
+            return;
+        }
+
+        if (document.hidden) {
+            return;
+        }
 
         var ctx = document.getElementById('weeklyChart');
         if (!ctx) {
             return;
         }
 
+        isPolling = true;
+
         var userTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
 
         var url = type === 'service'
             ? `/services/${currentServiceId}/daily-stats.json?timezone=${encodeURIComponent(userTimezone)}`
             : `/services/${currentServiceId}/daily-stats-by-user.json?timezone=${encodeURIComponent(userTimezone)}`;
 
+        try {
+            const response = await fetch(url);
+            if (!response.ok) {
+                throw new Error('Network response was not ok');
+            }
 
-        return fetch(url)
-            .then(response => {
-                if (!response.ok) {
-                    throw new Error('Network response was not ok');
-                }
-                return response.json();
-            })
-            .then(data => {
+            const data = await response.json();
                 labels = [];
                 deliveredData = [];
                 failedData = [];
@@ -277,10 +285,38 @@
                     }
 
                     return data;
-                })
-                .catch(error => console.error('Error fetching daily stats:', error));
-        };
-        setInterval(() => fetchData(currentType), 25000);
+        } catch (error) {
+            console.error('Error fetching daily stats:', error);
+        } finally {
+            isPolling = false;
+        }
+    };
+
+    function startPolling() {
+        fetchData(currentType);
+
+        pollInterval = setInterval(() => {
+            fetchData(currentType);
+        }, POLL_INTERVAL_MS);
+    }
+
+    function stopPolling() {
+        if (pollInterval) {
+            clearInterval(pollInterval);
+            pollInterval = null;
+        }
+    }
+
+    document.addEventListener('visibilitychange', () => {
+        if (document.hidden) {
+            stopPolling();
+        } else {
+            stopPolling();
+            startPolling();
+        }
+    });
+
+    startPolling();
     const handleDropdownChange = function(event) {
         const selectedValue = event.target.value;
         currentType = selectedValue;

app/assets/javascripts/modules/all.mjs

@@ -14,7 +14,6 @@ import Button from 'govuk-frontend/components/button/button';
 import Radios from 'govuk-frontend/components/radios/radios';
 
 // Modules from 3rd party vendors
-import morphdom from 'morphdom';
 
 /**
  * TODO: Ideally this would be a NodeList.prototype.forEach polyfill
@@ -67,13 +66,8 @@ var Frontend = {
   "initAll": initAll
 }
 
-var vendor = {
-  "morphdom": morphdom
-}
-
 // The exported object will be assigned to window.GOVUK in our production code
 // (bundled into an IIFE by RollupJS)
 export {
-  Frontend,
-  vendor
+  Frontend
 }

app/assets/javascripts/socketio.js

@@ -1,11 +1,3 @@
-function debounce(func, wait) {
-  let timeout;
-  return function (...args) {
-    clearTimeout(timeout);
-    timeout = setTimeout(() => func.apply(this, args), wait);
-  };
-}
-
 document.addEventListener('DOMContentLoaded', function () {
   const isJobPage = window.location.pathname.includes('/jobs/');
   if (!isJobPage) return;
@@ -15,69 +7,105 @@ document.addEventListener('DOMContentLoaded', function () {
   const featureEnabled = jobEl?.dataset?.feature === 'true';
   const apiHost = jobEl?.dataset?.host;
 
-  if (!jobId) return;
+  if (!jobId || !featureEnabled) return;
 
-  if (featureEnabled) {
-    const socket = io(apiHost);
+  const DEFAULT_INTERVAL_MS = 10000;
+  const MIN_INTERVAL_MS = 1000;
+  const MAX_INTERVAL_MS = 30000;
 
-    socket.on('connect_error', (err) => {
-      console.error('Socket connect_error:', err);
-    });
+  let pollInterval;
+  let currentInterval = DEFAULT_INTERVAL_MS;
+  let isPolling = false;
 
-    socket.on('error', (err) => {
-      console.error('Socket error:', err);
-    });
-
-    socket.on('connect', () => {
-      socket.emit('join', { room: `job-${jobId}` });
-    });
-
-    window.addEventListener('beforeunload', () => {
-      socket.emit('leave', { room: `job-${jobId}` });
-    });
-
-    const debouncedUpdate = debounce((data) => {
-      updateAllJobSections();
-    }, 1000);
-
-    socket.on('job_updated', (data) => {
-      if (data.job_id !== jobId) return;
-      debouncedUpdate(data);
-    });
+  function calculateBackoff(responseTime) {
+    return Math.min(
+      MAX_INTERVAL_MS,
+      Math.max(
+        MIN_INTERVAL_MS,
+        Math.floor((250 * Math.sqrt(responseTime)) - 1000)
+      )
+    );
   }
 
-  function updateAllJobSections() {
+  async function updateAllJobSections() {
+    if (document.hidden || isPolling) return;
+
+    isPolling = true;
+    const startTime = Date.now();
+
     const resourceEl = document.querySelector('[data-socket-update="status"]');
     const url = resourceEl?.dataset?.resource;
 
     if (!url) {
-      console.warn('No resource URL found for job updates');
+      isPolling = false;
       return;
     }
 
-    fetch(url)
-      .then((res) => res.json())
-      .then(({ status, counts, notifications }) => {
-        const sections = {
-          status: document.querySelector('[data-socket-update="status"]'),
-          counts: document.querySelector('[data-socket-update="counts"]'),
-          notifications: document.querySelector(
-            '[data-socket-update="notifications"]'
-          ),
-        };
+    try {
+      const response = await fetch(url);
+      const data = await response.json();
 
-        if (status && sections.status) {
-          sections.status.innerHTML = status;
-        }
-        if (counts && sections.counts) {
-          sections.counts.innerHTML = counts;
-        }
-        if (notifications && sections.notifications) {
-          sections.notifications.innerHTML = notifications;
-        }
-      })
-      .catch((err) => {
-        console.error('Error fetching job update partials:', err);
-      });
+      const sections = {
+        status: document.querySelector('[data-socket-update="status"]'),
+        counts: document.querySelector('[data-socket-update="counts"]'),
+        notifications: document.querySelector('[data-socket-update="notifications"]'),
+      };
+
+      if (data.status && sections.status) {
+        sections.status.innerHTML = data.status;
+      }
+      if (data.counts && sections.counts) {
+        sections.counts.innerHTML = data.counts;
+      }
+      if (data.notifications && sections.notifications) {
+        sections.notifications.innerHTML = data.notifications;
+      }
+
+      const responseTime = Date.now() - startTime;
+      currentInterval = calculateBackoff(responseTime);
+
+      if (data.stop === 1 || data.finished === true) {
+        stopPolling();
+      }
+
+    } catch (error) {
+      console.error('Error fetching job updates:', error);
+      currentInterval = Math.min(currentInterval * 2, MAX_INTERVAL_MS);
+    } finally {
+      isPolling = false;
+    }
   }
+
+  function startPolling() {
+    updateAllJobSections();
+
+    function scheduleNext() {
+      if (pollInterval) clearTimeout(pollInterval);
+      pollInterval = setTimeout(() => {
+        updateAllJobSections();
+        scheduleNext();
+      }, currentInterval);
+    }
+
+    scheduleNext();
+  }
+
+  function stopPolling() {
+    if (pollInterval) {
+      clearTimeout(pollInterval);
+      pollInterval = null;
+    }
+  }
+
+  document.addEventListener('visibilitychange', () => {
+    if (document.hidden) {
+      stopPolling();
+    } else {
+      startPolling();
+    }
+  });
+
+  window.addEventListener('beforeunload', stopPolling);
+
+  startPolling();
 });

app/templates/components/ajax-block.html

@@ -1,14 +1,3 @@
 {% macro ajax_block(partials, url, key, finished=False, form='') %}
-  {% if not finished %}
-    <div
-      data-module="update-content"
-      data-resource="{{ url }}"
-      data-key="{{ key }}"
-      data-form="{{ form }}"
-    >
-  {% endif %}
-    {{ partials[key]|safe }}
-  {% if not finished %}
-    </div>
-  {% endif %}
+  {{ partials[key]|safe }}
 {% endmacro %}

package-lock.json

@@ -19,7 +19,6 @@
         "govuk-frontend": "2.13.0",
         "gulp-merge": "^0.1.1",
         "jquery": "3.7.1",
-        "morphdom": "^2.7.7",
         "playwright": "^1.55.0",
         "python": "^0.0.4",
         "query-command-supported": "1.0.0",
@@ -11204,12 +11203,6 @@
       "integrity": "sha512-vKivATfr97l2/QBCYAkXYDbrIWPM2IIKEl7YPhjCvKlG3kE2gm+uBo6nEXK3M5/Ffh/FLpKExzOQ3JJoJGFKBw==",
       "dev": true
     },
-    "node_modules/morphdom": {
-      "version": "2.7.7",
-      "resolved": "https://registry.npmjs.org/morphdom/-/morphdom-2.7.7.tgz",
-      "integrity": "sha512-04GmsiBcalrSCNmzfo+UjU8tt3PhZJKzcOy+r1FlGA7/zri8wre3I1WkYN9PT3sIeIKfW9bpyElA+VzOg2E24g==",
-      "license": "MIT"
-    },
     "node_modules/ms": {
       "version": "2.1.3",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",

package.json

@@ -35,7 +35,6 @@
     "govuk-frontend": "2.13.0",
     "gulp-merge": "^0.1.1",
     "jquery": "3.7.1",
-    "morphdom": "^2.7.7",
     "playwright": "^1.55.0",
     "python": "^0.0.4",
     "query-command-supported": "1.0.0",