Ion-checkbox toggle all Vue.js

Trying in vain to get a working solution, this is the closest I have, but for some reason when I select one checkbox they all select, and when I check the box that’s supposed to check all it only does it one way all on, but not all off.

        select() {
            this.selected = [];
            if (this.selectAll) {
                for (let i in this.loadedSwap) {

This is my repeated checkbox in a v-for

<ion-checkbox class="mr-2 border-white" :id="" v-model="selected" number></ion-checkbox>

And my check all

<ion-checkbox  class="mr-2 border-white" v-model="selectAll" @click="select"></ion-checkbox>

Thank’s Aaron, that was helpful. Had to add object key into my downloaded object for the checkbox state. Thought v-model would do its thing, but clearly not in Ionic land.