Added scrollback to top on page change in WBLiveLogs.

frontend/src/js/component/wb-live-logs.js

@@ -1,4 +1,4 @@
-import { h, Component } from 'preact';
+import { h, Component, createRef } from 'preact';
 import makeArvadosRequest from 'make-arvados-request';
 import WBPagination from 'wb-pagination';
 
@@ -6,6 +6,7 @@ class WBLiveLogs extends Component {
   constructor(...args) {
     super(...args);
     this.state.page = 0;
+    this.terminalRef = createRef();
   }
 
   componentDidMount() {
@@ -39,6 +40,7 @@ class WBLiveLogs extends Component {
           .map(a => a.properties.text.trim()).join('\n'),
         numPages: Math.ceil(xhr.response.items_available / itemsPerPage)
       });
+      this.terminalRef.current.scrollTo(0, 0);
     });
   }
 
@@ -47,7 +49,7 @@ class WBLiveLogs extends Component {
       <div>
         <WBPagination activePage={ page } numPages={ numPages }
           onPageChanged={ page => { this.state.page = page; this.fetchData(); } } />
-        <pre class="word-warp terminal">
+        <pre class="word-warp terminal" ref={ this.terminalRef }>
           { content }
         </pre>
       </div>