Sorting by level works as expected

build/process_spells.js

@@ -28,7 +28,7 @@ let indexedSpells = spellsWithIDs.map(spell => {
     id: spell.id,
     name: spell.name,
     classes: spell.classes,
-    level: spell.level,
+    level: spell.level.toLowerCase() === 'cantrip' ? 0 : parseInt(spell.level),
     link: '/spell/' + spell.id,
   }
 })

src/components/Spellitem.vue

@@ -1,7 +1,7 @@
 <template>
   <div v-bind:class="{'checked': checked}">
     <div class="item-primary">
-      {{level}}
+      {{spell.level}}
     </div>
     <div class="item-content has-secondary">
       <router-link :to="spell.link">
@@ -35,9 +35,6 @@ import { capitalize } from '../utils'
 
 export default {
   computed: {
-    level () {
-      return this.spell.level.toLowerCase() === 'cantrip' ? '0' : this.spell.level.charAt(0)
-    },
     school () {
       return capitalize(this.spell.school)
     },