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Balazs Peak
46,160 PointsGuil updated state based on the previous state directly
Guil updated state based on the previous state directly. According to his teachings in the new course, this might cause state inconsistency, because React's setState is sometimes called asynchronously for performance reasons - this makes passing a callback function to the setState method a better solution compared to passing an object.
Reference: https://teamtreehouse.com/library/update-state-based-on-previous-state
I refactored toggleConfirmationAt() function by passing a callback to the setState, instead of an object.
toggleConfirmationAt = indexToChange =>
this.setState((prevState) => {
return {
guests: prevState.guests.map((guest, index) => {
if (index === indexToChange) {
return {
name: guest.name,
isConfirmed: !guest.isConfirmed
};
}
return guest;
} // map function callback function
) // map function call
} // object returned by setState parameter callback function
} // setState parameter callback function
);
1 Answer
Saqib Ishfaq
13,912 Pointsdefinitely the right thing to do! i did the same>>>
toggleConfirmationAt = indexToChange => {
this.setState( (prevState) => {
return {
guests: prevState.guests.map( (guest,index) => {
if(indexToChange === index){
return {
...guest,
isConfirmed : !guest.isConfirmed
};
}
return guest;
})
}
});
}