@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' } } } },