Answer by Just code for Is there any way to set a background colour to the full column for Saturday and Sunday in 'React Full Calendar'

You can use dayPropGetter property to customize it

Here is how your function should looks like

const customDayPropGetter = (date: Date) => {  if (date.getDate() === 7 || date.getDate() === 6)    return {      className: 'special-day',      style: {        border: 'solid 3px '+ (date.getDate() === 7 ? '#faa' : '#afa'),      },    };  else return {};};

and assign function like this

 dayPropGetter={customDayPropGetter}

demo

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