Null.vue

<template>
  <div class="q-pa-md">
    <q-badge color="primary" class="q-mb-lg">
      Model: {{ getNullLabel(basicModel) }} (step 1)
    </q-badge>

    <q-slider
      v-model="basicModel"
    />

    <q-badge color="secondary" class="q-mb-lg">
      Model: {{ getNullLabel(limitModel) }} (10 to 70, step 1, inner 20 to 55)
    </q-badge>

    <q-slider
      v-model="limitModel"
      color="secondary"
      :min="10"
      :max="70"
      :inner-min="20"
      :inner-max="55"
    />
  </div>
</template>

<script>
import { ref } from 'vue'

export default {
  setup () {
    return {
      basicModel: ref(null),
      limitModel: ref(null),

      getNullLabel (val) {
        return val === null ? 'null' : val
      }
    }
  }
}
</script>