import { SettingsSpec , TooltipValueFormatter , isTooltipProps } from '../../specs/settings' ; import { createCustomCachedSelector } from '../create_selector' ; import { getSettingsSpecSelector } from './get_settings_specs' ; internal export const getTooltipHeaderFormatterSelector = createCustomCachedSelector ( [ getSettingsSpecSelector ] , getTooltipHeaderFormatter ) ; function getTooltipHeaderFormatter ( settings ) { const { tooltip } = settings ; if ( tooltip && isTooltipProps ( tooltip ) ) { return tooltip . headerFormatter ; } }