Store all emails, not just ids, so they can be used elsewhere

src/components/MailTable.vue

@@ -1,13 +1,11 @@
 <template>
-  <p>Number selected: {{emailSelection.ids.size}}</p>
-
   <table>
     <tbody>
       <tr v-for="email in emails" :key="email.id" :class="[email.read ? 'read' : '']">
         <td>
           <input type="checkbox" 
-                  :checked="emailSelection.ids.has(email.id)"
+                  :checked="emailSelection.ids.has(email)"
-                  @click="emailSelection.toggle(email.id)" />
+                  @click="emailSelection.toggle(email)" />
         </td>
         <td>{{email.from}}</td>
         <td>

src/composition/useEmailSelection.js

@@ -1,6 +1,6 @@
 import { ref, reactive } from 'vue';
 
-let ids = new Set(['1', '5']);
+let ids = new Set();
 export const useEmailSelection = function(){
 
   let emailSelection = reactive({