# Initial State: { isAgeLessThan18: false } # Initial View - isAgeLessThan18? if yes, then show error, else keep error hidden. - View: error Hidden # Event - Read Input. - Use that Input to calculate Age. # new state - if age < 18 then set state to { isAgeLessThan18: true } # new view - isAgeLessThan? if yes, then show error, else keep error hidden. - View: error Shown.