Unravel the thread

A thread is a collection of e-mail messages, and the thread view makes up the left-hand pane of our application. It looks something like this:

// app/view/threads/Threads.js
Ext.define('Postcard.view.threads.Threads', {
    extend: 'Ext.DataView',
    xtype: 'threads',
    cls: 'thread-view',
    viewModel: 'threads',
    controller: 'threads',
    border: true,
    deferEmptyText: false,
    emptyText: 'No messages',
    autoScroll: true,
    itemSelector: '.thread',
    bind: '{threads}'
    tpl: new Ext.XTemplate('<tpl for=".">',
        '<div class="thread">',
            '<div class="date">{lastMessageOn:date("H:m")}</div>',
            '<div class="details">',
                '<div class="header">{people} - {subject}</div>',
                '<div class="body">{[this.stripHtml(values.lastMessageSnippet)]}</div>',
            '</div>',
        '</div>',
    '</tpl>', {
        stripHtml: function...