@acros, as @Hawkeye64 mentioned - in my case it’s [ in App.vue ]

  created () {
    this.$q.iconMapFn = (iconName) => {
      if (iconName.startsWith('chevron_left') === true) {
        return { cls: 'fal fa-chevron-left' }
      }
      if (iconName.startsWith('chevron_right') === true) {
        return { cls: 'fal fa-chevron-right' }
      }
    }
  },

@acros, as @Hawkeye64 mentioned - in my case it’s [ in App.vue ]

  created () {
    this.$q.iconMapFn = (iconName) => {
      if (iconName.startsWith('chevron_left') === true) {
        return { cls: 'fal fa-chevron-left' }
      }
      if (iconName.startsWith('chevron_right') === true) {
        return { cls: 'fal fa-chevron-right' }
      }
    }
  },