React Native toggle add/remove element in an array based off toggling a button-CodePudding

I have a TouchableOpacity that can be both pressed and unpressed.

Here is my useState variable:

const [isPressMonday, setIsPressMonday] = useState(false);

and here is my toggling function:

    setIsPressMonday(!isPressMonday);
    setDays(days => [...days, 'Monday']) 

  };

The thing is, when a user un-clicks the button, it should remove Monday from the array. This would be simple if I could just check if(!isPressMonday) and remove it from the array, but the default is false so that is almost always true

CodePudding user response：

You don't need to check with isPressMonday state instead check if 'Monday' present in days state. If yes, remove else, add.

//assuming 'days' is your array state name
setIsPressMonday(isPressMonday => !isPressMonday);
const index = days.indexOf('Monday');
if (index !== -1) {
  let tempDays = days
  tempDays.splice(index, 1);
  setDays(tempDays)
}
else {
  setDays(days => [...days, 'Monday'])
}