re-implemented without timer

src/components/cylc/log/Log.vue

@@ -20,7 +20,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
     v-for="(log, index) in computedLogs"
     :key="index"
     :class="wordWrap ? 'text-pre-wrap' : 'text-pre'"
-  >{{ log }}</span></pre>
+  >{{ log }}</span>
+  </pre>
 </template>
 
 <script>
@@ -84,6 +85,15 @@ export default {
       }
       return logLine
     }
+  },
+
+  watch: {
+    computedLogs: {
+      handler (val, old) {
+        this.$emit('updating')
+      },
+      deep: true
+    }
   }
 }
 

src/views/Log.vue

@@ -170,6 +170,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
             :logs="results.lines"
             :timestamps="timestamps"
             :word-wrap="wordWrap"
+            @updating="updating"
           />
           <!-- a div to use for autoscrolling -->
           <div class="auto-scroll-end"></div>
@@ -414,7 +415,6 @@ export default {
 
   data () {
     return {
-      timer: null,
       autoScroll: false,
       controlGroups: [
         {
@@ -498,6 +498,11 @@ export default {
         el.scrollIntoView(options)
       }
     },
+    updating () {
+      if (this.autoScroll) {
+        this.scrollToElement('auto-scroll-end', { behavior: 'smooth' })
+      }
+    },
     setOption (option, value) {
       // used by the ViewToolbar to update settings
       this[option] = value
@@ -582,25 +587,12 @@ export default {
     },
   },
 
-  beforeUnmount () {
-    clearInterval(this.timer)
-  },
-
   watch: {
     jobLog (val, old) {
       // reset the filename when the log mode changes
       this.file = null
       // go back to last chosen job if we are switching back to job logs
       this.relativeID = val ? this.previousRelativeID : null
-    },
-    autoScroll (val, old) {
-      if (old) {
-        clearInterval(this.timer)
-      } else {
-        this.timer = setInterval(() => {
-          this.scrollToElement('auto-scroll-end', { behavior: 'smooth' })
-        }, 1000)
-      }
     }
   },