computed_component.vue

<template>
  <div :class="themeDiv"></div>
</template>

<script type="text/javascript">
export default {
  props: {
    plan: {
      required: true,
      type: String
    }
  },
  computed: {
    themeDiv: function () {
      if (this.plan === 'pro') {
        return 'blue'
      } else if (this.plan === 'trial') {
        return 'soft-blue'
      } else {
        return 'orange'
      }
    }
  }
}
</script>