v-for Elements in iteration expect to have 'v-bind:key' directives vue/require-v-for-key code example
Example: vue js Elements in iteration expect to have 'v-bind:key' directives
try to add v-bind:key="type" in your li
//example
`<li class="list-group-item" v-for="type in types" v-bind:key="type"></li>`